Softlayer LayeredTech They are the best but a little pricey. They don't accept Paypal but you can go to their reseller at Server4Sale that accept paypal.
Proxy sites aren't stable on shared environments. You need to opt for dedicated hosting for your websites smooth functioning.
Not all the VPS allow proxies either, or they do restrict its use for intranet purposes, not public access.
It will be easier for you to look for dedicated server to run your own proxy. I think you will not need a higher end server a basic plan will be enough for you.
Your not going to find many hosting companies, reliable ones anyway that allow proxies. Your more than likely going to have to go dedicated.