I have sold many things on Ebay...and bought many things as well. I personally believe Ebay is much safer than Craigslist. Much safer, by far! First of all, yes, you need a Paypal account. It's free to sign up. Sign up for Ebay, creating a member "name" for yourself. Once you have signed up, start browsing. Once you find something you like, take a look at the seller's info. You find a short version of this information on the top right corner of the auction page. You will see a number, sometimes a large number (like in the thousands) and sometimes a smaller number and even some colored stars. Don't let a small number scare you or give you total confidence when you see a large number. LOOK at the percentage of positive feedback. The percentage of positive feedback is important. Obviously the higher the number, the better the person you are dealing with. You can also take a peek at the seller's feedback to give you and idea of the kind of seller they are (do they have positive feedback for fast shipping or not...you can read what people have said about that particular seller).
Next, take a look at the description they have. Is it clear? IF not, contact them with any additional questions you may have. LOOK closely at their return policy, if they have one at all. Many sellers start their auction with an opening bid. This is a starting bid. Let's say your diaper bag has a starting bid of $2 like you stated. What is the MAXIMUM you are willing to pay? Let's say you are willing to pay no more than $15.00 for this diaper bag. So, you place your bid for $2 but with a MAX of $15. IT does not mean it will sell for $15. This is where the bidding wars begin. The "starting" bid will continue to increase in small increments. So, if you bid on it for $2.00 but place a max bid of $15.00, say I come along and bid on it for the next increment but I place a max bid for $20.00, now I've got a better chance to win...because my max bid just outbid you. Always start with the starting bid (when there are other bids, it will tell you the next increment to bid) but you always have the option to place a max bid OR a higher bid than the next increment stated. Placing a max bid allows you the freedom of not having to continuously watch your item. As the other bids roll in, as long as their bids are still lower than yours, your max bid gives you a little more room to win the item if you really want it bad enough. The seller doesn't approve of the bids. This is all Ebay...it's what makes it fair. Yes, it's absolutely possible to get the diaper bag for $3 as long as you were the only bid. Some sellers also offer a "Buy it Now" option. This option is very nice, indeed because it enables you to bypass the bidding process but you can also expect to pay a higher amount. But, if this is something you really want and don't want to lose it, then choose the "Buy it now" option. Always take a peek at the shipping charge too! Some seller's place their starting bids very low but place a higher shipping charge. It is legal to do this as they include a shipping fee into that shipping charge. Whenever I have sold on Ebay, I generally include a small shipping fee (it's always a minimal amount for me) but I've seen sellers charge outrageous shipping fees. Use your judgment and decide what is fair. Ebay is fun and safe. Yes, there can be scammers on Ebay. Deceptive people can be found anywhere but Ebay and Paypal are very good at helping you should some problem arise. Once you get your item, and you are happy, don't forget to leave feedback for the seller. Likewise, the seller usually gives you feedback as well so this will help YOU in your buying and possible selling ventures.