A Comm add-on only requires 20 solo flights. To solo you'll have to show you can do steep turns (don't worry about holding altitude) and stalls (all power off.) The big difference is launch failures. Almost everyone in the US does aerotows so you deal with the rope breaking at 200 feet. You also have to show you can maneuver on tow, almost like doing formation flight. And you have to plan your pattern. I don't see it in the regs anymore but it used to say land and stop within a 100 feet of a line but not cross the line (simulates landing in a field with a fence.) Going at it, it can be done in a couple of weekends. There are commerical operations and clubs. The commercial schools are more like a normal flight school. The clubs will charge a fee to join but the rates are cheaper. If you're just going to add the rating and move on, I'd say do the commercial operation. If there is a club in your area and think you might stick with it (need to renew the CFI?) clubs are lot of fun. Check out SSA.org.
I don't think I spent a grand but that was 20 years ago.