Web Proxy List by Access
While you can easly find a lot of free web proxies on the Internet there are paid one aswell.
Free proxies suffer from huge bandwidth and high proccessor load that is why you'll definitely experience troubles with free proxies.
Paid proxies serve only subscribed users' requests. So you will get quicker response from them. Again paid proxies usually have support team that will help you if you need any assistance.
Some proxies sell monthly or even weekly subscriptions while there are paid proxies that measure the bandwidth for each user and sell bandwidth credits.