Reships/package forwarders are always an option if sites don't ship to you. It'll cost you a bit of money for shipping, of course. You should also be ready to provide documentation in the form of a drivers license or an ID card if you choose to go with this route, as reshippers are currently trying to crack down on reshipping fraud, and GPUs are rather valuable items.
Many reship services don't go to Iran, but I did find that
Reship.com delivers to Iran. I know from experience that they're not the cheapest service while I lived outside the US, but looking around should yield cheaper options if there are any.
Depends on the country where you live and how good postage you have there. In some countries, believe me it 100% worths to use package forwarders.
OP no one is going to supply you with cheap GPUs, you have to sit and look for them online, to make this deal easier for you, use this website:
https://www.nowinstock.net <-- they update stocks and sometimes you can find gpus in very cheap price.