There are some important things to consider when buying wholesale items on eBay, or generally buying wholesale online. There are some things I like to keep in mind when I look for a good enough deal that I can turn around a profit. Questions you should ask yourself before purchasing are, for example, how much money can I invest, how much can I afford to lose, what are the best selling brands/types of items, how much is shipping to me, what is my time frame of receiving the merchandise, what season is selling best right now, do I want to buy it now to resell later, how much inventory do I have now and how quickly do I need to make a decision.
A good rule of thumb is to try to pay 1/3 or less of the original retail value of an item. I think of it this way: if I buy something at 25% of retail value and resell it at 40% of retail value, I have made a profit. A number version of this sentence would be: if I buy something at $25 that has a retail value of $100 and I resell it for $40, I have made a profit.
When purchasing your wholesale lot, ALWAYS include the shipping charge in your 1/3 or less calculation. The price of shipping can determine whether a deal that seems good actually isn't. If you are buying 50 pair of sunglasses for $50, but the shipping is $150, instead of each pair being $1.00 each, they end up being $4.00 each. If they are guaranteed authentic high retail value sunglasses, this might be a good deal. If they are unknown brand or quality glasses, it is not such a great deal
Speaking of authentic... It is important to buy your items from a reputable seller who has done a lot of previous business with prior new with tags items plus has number positive feedback over an extended period of time associated with new with tags items. There are some fly by night sellers who buy 20 things or so to have 20 positive feedback and then sell something. If you don't look at the feedback, you may assume the seller has a good reputation, when the reputation is based purely on buying rather then selling. Most likely you will be spending a good deal of money to start or add to your inventory, so it is very important to do your research with the seller.
Beware of auctions that are "double your bid" type of auctions. You will find a lot of these for Gymboree items. If your winning bid is $50 and shipping is $12.50, you are getting $100 worth of Gymboree for $62.50. Now it is 62.5% of retail value instead of 50%, which is still really high. $100 of Gymboree items could only be 2-3 items and they are from any line and any size the seller chooses to send you. This is a high risk if you are looking to resell because you don't know what you are getting, how it will resell or what else you will need to match your items in order to get them to sell.
Remember, always do your research, check the fine print and don't impulse buy a wholesale lot and you will be on your way to making a profit on eBay!