My 2 cents has to go with the consensus, the McGregor 26 might be fine for a small lake but I wouldn't take it out on the open ocean. For what you are planning to start with, I might look at Hunter's or Catalina's. Even ComPac has some nicely built trailer sails.
Besides places like Craig's List, there are weekly sales things such as "Sailboat Trader", also you can cruise
the different marinas and see what might be available. Chances are, for your price range, you're going to have to supply some TLC and elbow
grease. This isn't entirely bad if you consider it as training for a larger, more complex boat down the road. You might even pick up an issue or two of "Good Old Boat" as they tend to emphasize the smaller, more economical boats.
As someone once told me, more years ago than I care to remember, look for the things you can't change. Things like size, hull
design, layout, etc. but only give secondary priority to the things you can more easily change. Wood trim looks terrible? Fine that can be fixed. You want self tailing
winches? Fine, start saving. And on, and on!
If it's any consolation, yo those decades ago when I started, I too looked at the Mc 26. I ended up with a Morgan
32 as my first boat and was quite pleased.
Good luck, have fun, boat shopping
can be a hoot. I might also suggest that you find someone to mentor you. Could be here, could be someone at a local marina. Haven't met too many sailors that don't like to talk. You could really use someone to help wipe away the stars in the eyes and perhaps prevent an expensive mistake.