I think that a thread needs to be started for people -particularly newer players- to navigate all these pokemon buying web sites, so here is a resource for the average pokemon consumer.
Let's look at different Pokemon Card carrying sites and their uses:
This site's variety is huge, and they are one of the few that carry Japanese cards that are newer. They also have some very good prices in the Booster Pack/Box areas, although they also have some pretty bad ones. Outside of that pretty average prices, but I applaud their vast variety.
Troll and Toad
This site is the best as far as their single card prices go in general, but it's a minefield. There will be a couple bad prices mixed in, as well as less-than-desirable conditions on many cards.. Another thing that T&T is notorious for is being less than honest. Their staff they send to events tends to overcharge and take advantage of newer players. (I'm not saying they all do this, but just hanging around in their store at Nationals and other events I've seen this with my own eyes.) Although, you cannot beat a lot of their singles prices and their shipping rates are superb. ($0.99 for up to 100 singles.) They do make sure to give you reciepts, but it's your responsibility to save them. Another member posted a card he recieved in less-than-desirable condition, and I remember my friends and I have gotten cards that weren't in the best of condition. I recieved one with a sticky residue on it. So, I'd steer clear of buying any overly-expensive cards and/or collectibles. On January 5, 2012, I recieved a shipment from them of 4 RH AbiliBoars, 4 Tepigs, and 2 Pignites. The cards were protected only by two pieces of paper on each side of the stack. No toploaders, no sleeves, nothing. Needless to say all of them were scratched severely and many of the commons had gouges in them. (Luckily the Emboars didn't.) If you can find the same price for what you need elsewhere (or maybe even just a little worse price) I would go elsewhere without a doubt.
BB Toy Store
This is the place for cheaper plushies and toys. Most prices on this site are pretty average, and their playing supplies section isn't too shabby.
This site is bigger than BB Toy Store, but more expensive with their pokemon toys/plushies. Prices here are exponential compared to many other sites, but it has much better pokemon toy selection. It has the highest quality in general toys/plushies, but quality comes with a price.
This is where you want to go for general electronics, games, and movies. It has pages and pages of games and movies, everything from new releases to the oldies. I found movies I didn't even know existed
This one's a mess. It's dozens of pages of random pokemon-related items, from cards to plushies, party streamers to games. It's the equivilent of a pokemon flea-market, except more like store prices and store quality. (And definitely more cleanliness than a flea-market.)
This site has quality product, average pricing, and a medium variety. One thing I do like is the large amount of sales that seem to go on on this site. This seems like a good site for standard playing equipment like sleeves, deckboxes, etc.
This site always sends in superb condition, and often runs specials. Many of their more rare singles are drastically overpriced, so I'd look elsewhere for anything that isn't commons.
This is a super-site for Japanese merchandise, literally shipped straight from Japan. They have just about everything imaginable, from school supplies, to clothing, to even mirrors. If you're looking for Japanese merchandise, this is a hotspot. However, as with most Japanese Pokemon things, it is VERY pricey. Some plushies range between $20 - $500.
This is a fantastic site for deals. Their prices often even top that of Troll and Toad, which is superb. Many useful cards are only a penny. They have a pretty good selection, but it's difficult to navigate their site and find what you're looking for. If you've got an eye for deals and/or are hunting for commons/uncommons, you may want to try this site. However, the shipping here is quite costly, weighing in at around 70 cents per single.
Stop 2 Shop
I've got good reports of service and card condition. I checked the site out, and their prices seem to vary quite a bit. Some prices are very low, like their 20 cent cards. However, on many of their holos the prices are very high. You'll have to hunt through the prices to get a good deal. However, if you're building an extreme rogue this is definitely one to check out. All sites raise the prices by how much people buy the cards, but this one is to the extreme. Holos that are used very sparsely get bumped up pretty high for what they are.
The PokeBeach Buying Forum
If you feel like haggling out a bargain with a seller, or posting a thread in search of something in particular, you can post here and try your luck with our Verified Sellers. However, be careful. Some are willing to give you a deal, but some can be quite deceptive.
Well, there we have it. Now, here are some tips for shopping Pokemon online:
1. Compare, compare, compare. Don't just visit one site and immediately buy, go to ten different sites and find out where you can get the best price.
2. Quality of the buy = amount of product / Cost
In this case, the highest number wins. If one site sells 50 sleeves / $2, but another site sells 100 sleeves / $3, the better buy is the 100 sleeve buy, because it boils down to 33.3 sleeves per dollar and the other boils down to 25 sleeves per dollar. This works in quantitative buys only.
3. Watch the brands. Monster and Ultra Pro are high-quality products, while some generic knock-offs will tear easily. You can look for reviews online and ask around players around your local area if a product is good or not. One product this is very evident in is plushies. Jakks is a high-quality brand of plushy, while some knock-offs will have misshapen bodies, factory errors, etc.
4. Don't take people's word for face value. Including mine! I encourage people to question things and do their own research. If somebody -in the buyer's forum, let's say- tells you that a card he/she has is valuable and they're willing to cut you a special deal, look up what that card is worth on several sites before you take the bait, because you never know when there will be a hook.
I hope Pokemon players/consumers will find this useful in making various purchases. (And please post to keep this resource at the top for others to use.)
(If the mods want to move this to the Training Facility, that's fine with me. Wherever it will be most useful.)