sock5 proxy are simple proxys you can buy nearly everywhere. There are many sites out there. It will give you just a different IP if you log in via a sock5 proxy.
Many sock5 proxy's are flagged because they are already known for botting, hacking, mailware, spamming and so on. So you shouldn't buy list's with 1.000 sock5 proxy because there are already a lot of people out there who are using them. The safest way is to set them up by yourself on trusted / nonflaged vmserver's. But that is more expensiv. Or use sock5 proxy from a site that isn't well known. There is no guide to 100% safety