There really are a lot of places to get purchase proxies, and what you are using them for plays a role in what proxies you should purchase.
However, I find that for 99% of people who are using proxies outside of a business scenario that the shared proxies from www.Proxy-hub.com are an affordable and useful option. They have great support and will keep your IP hidden from Google, many proxies you purchase actually don't do this very well.
I have been using them for over 4 years now with zero issues and I purchase 30 shared proxies every month for scrapping data.
Hope that help!