I hope you can do it when it's more financially viable. At least look around though. It depends on the art and locale.
Depends on the type of MA you're after. If it's something more common art you might be able to swing it for 100 a month. I've seen Shaolin Kung Fu places start at 90. If it's a really popular MA like BJJ you'll really have to research and visit different schools and look at different price ranges because it can range from okay (100) to expensive (160).
Treat yourself when they come and make it a special day!
MCMAP from what I've seen looks legit.
Muay since 2007?? Wow, that's amazing. I had to quit because I'm not big on getting hit.
Purple belt in five years isn't bad to be honest. I wouldn't think of that as a bad thing at all. Your place offers both MT and BJJ? You sound like a badass.