Personally, I like the idea of buying a used MEC on eBay, although I haven't done it myself. I sold a couple.
A lot of people start reloading with one of the cheaper MECs and eventually move up to a faster model. For that reason, there are always a number of used 600s and 650s for sale on eBay. If you buy one that way, you can get your money back when you move up and re-sell the 650.
You can download a manual free off of MEC's web site or order a paper copy for $5.
http://www.mecreloaders.com/OwnerManual ... anuals.asp
Parts are cheap and easy to order online. If the reloader is dirty, so much the better - that will help hold the price down, and you can clean it up easily.
If it needs repairs that you can't do yourself (which is not likely!) just pack it up and send it to MEC, they will rebuild it for a small fee and you will have the equivalent of a brand new one.
Or, if all else fails, sell it on eBay like the other guy did!
Some people don't like the 650 because it doesn't have a resizer (not one that works, anyway). I started with a couple of 650's (12 and 28 ga) and I like them. I never needed a resizer when using hulls that have brass heads, like AA and STS. You may or may not need one with cheap hulls that have steel heads.
One thing to consider is whether you can justify paying the higher price for premium factory shells (AA or STS) when cheaper ones are available. I can, because I shoot a lot of tournaments that require factory shells, and I like the premium shells for competition, so I have lots of empty hulls of good quality with brass heads. If you want to economize on your factory shells, you might need a reloader with a resizer to load cheap hulls.
I don't recommend AA's for reloading, though. I load them once and throw them away. The separate basewad on the new-style AA's causes problems that are potentially dangerous. I prefer STS.
The bottom line is, it would be hard to lose more than a few bucks buying a used 650 on eBay, and the fun and experience would be worth it. Go for it!