Do I have to collect taxes on eBay?

You better have good records because eBay will report the gross sales (new requirement this year) to the IRS and they'll expect you to file a schedule c and se on the earnings. Goggle 1099-K.

You home state will get that info and demand income taxes and probably ask about sales taxes too.

Probably.

1) If you sell to anyone in your own state, then you must collect sales tax. If you sell only to users in other states, then this is not necessary.

2) If you make a profit by selling things for more than they cost you, then you must pay income tax. If you are only selling your old junk for less than it cost you, then this is not necessary.

3) If the profit (sales minus what it cost you to get the stuff that you sold) is $400 or more in any one year, then you must pay self-employment tax. If it is less than $400 in each year, then this is not necessary.

If you're doing that much business, sounds like you're not just selling some of your own stuff. If you live in a state with a sales tax, you need to get a sales tax license, and collect sales tax from buyers in your own state and remit it to the state.

And you need to file and pay income tax on your earnings.

You cannot specifically charge tax as you are not a bona fide retailer