Do you have any experience with VPS. I can only think of using some VPS and configuring it to use bots on those websites. This way you will not have to keep your PC ON all the time
i have(ubuntu 14 version) and i have also a very good list for you with some that accetp bitcoin too, shoot me a pm if you want
but you create your own vps for you bot, like i've done in the past for a renting bot, you need a vm + a vpn, there are some good free vpn with 1.5G per month as a bandwidth