Hi
I bought usd 100 worth of bitcoin in the past.
I guess about 20 years ago.
Are you OK? man I already start to be afraid of this forum

There was no bitcoin market exist at that time.
No bitcoin wallet.
They emailed me bitcoin address? and password.
I guess they were testing bitcoin in market and we can buy things in ebay with bitcoin.
even the worst altcoin usually have a wallet, maybe you got confused and I don't see how they would send you an email and password. to be clear:
are you typing from planet earth?
I found old harddisk drive that probably has this old bitcoin.
Do you think we can still cashing out this old bitcoin?
it depends, if you are talking about bitcoin "that bitcoin that was created 11 years ago" and your hard drive is good and you have private keys I think you can get access to that bitcoin. But if you're talking about your bitcoin "the one that was created 20 years ago" then you can't recover