More and more i am having offline businesses wanting me to create a website for them.
do i go reseller route like hostgator or just open an account for them with their credit card and forget about it?which one is more profitable and less headache?
Less headache would be to have them signup using your affiliate link. I would not advise you to setup the accounts using their card as this could lead to your commissions being voided due to being flagged as fraud.
The reseller approach would have the advantage of giving you a constant, growing income. When there’s little web design work, that web hosting income could prove very valuable. You would have to provide the customers with support, but it’s unlikely to be a serious nuisance once you’re past setting up the website.
I highly recommend you set up a reseller account. Since these businesses are online you can easily charge higher prices than you should if you were targeting online customers.
It is much better than simply referring your customers for a commission.
that’s what i am thinking to go with reseller account.
how much to charge 20$/month is a fair price?
- Research on reseller account. How much others are charging.
- Recover your cost and labour & headache
People are charging even less than $1/month at many places.
good luck.
how much to charge 20$/month is a fair price?
It depends on your costs and market. If you’re marketing locally and there’s only one other host in the area, charging $50 (and doing great business wise), then your $20 may even be unnecessarily cheap. 
If you’re trying to compete with Hostgator, Godaddy, 1and1 etc., you don’t stand a chance.
wanting me to create a website for them.
You could try to have a website maintenance fee addon to your hosting. Pricing it properly may be a bit tricky though. You could limit it with some “up to 2 hours of work per month” verbiage.
Reseller account is your best choice
I believe for your web site only shated web hosting account will be more then enough.