$100 is probably worth it, depending on what it is. Even though eBay is set up more for bulk sellers than the 3 item guys, if you're going to use it once and never again might want to think more about it. And yes, you can direct deposit into your bank account. I think it takes 2 or 3 days to get it completely set up, if I remember correctly. I think though, that being a new user, that PayPal MAY put a hold on your money (21 days or until item is confirmed delivered). I have seen where some sellers are experiencing this, not sure if it's a new deal or not. Also, after the hold is released the buyer has like 45 days or such to file a paypal claim if there's a problem.
You have to factor in shipping and stuff too, packaging, plus whatever USPS or UPS or whatever charges.
I had a pretty decent reputation as a buyer before I began selling and I've been a member for 10 years, about 4 when I began selling. I came back to selling after taking about 2 years off, and things have changed. Fees have gone up, but you can list for free. They also charge final value fee for shipping (which is stupid, but some dickheads charge $1 for a game and $15 for shipping so they could net $15 off the sale, instead of charge $15 and $1 shipping and make $13.50)
Some tips I have are only sell to US buyers. That is pretty much because you can easily track packages in the US (Required for Paypal seller protection)
There is a maximum amount you can charge for shipping, additional ways to ship can be considered as well, but the first has a max fee.
I generally don't sell to 0 feedback buyers unless they contact me, or people with 2 or more unpaid items in the past couple months. I've had less unpaids that way. When you are listing it is a box you can click.
BTW--WHAT ARE YOU SELLING? (You may be able to make your $100 here)