Skil still makes a decent 7 1/4" circular saw, and they aren't that much.  But I would do one of two things on your budget: Either get a simple and cheap circular saw like an entry level skil, craftsman, or porter cable, or shoot for the moon and look for a used workhorse in a good brand with magnesium plate, maybe worm drive, etc.  I got my Makita worm drive for about $75 used, and it will last me (and my son and maybe his son) a lifetime.. 
I have a skil that I bought new over 20 years ago, and it was great for many years, but then I used it to cut concrete for 10 hours straight, and that non-stop abuse took it's toll.  Yet for the past 9 years since then I have not removed the diamond blade and I use it for cutting concrete, tile, cement board, etc.  It is still working, although the bushing is shot and it wobbles quite a bit (but still keeps going).  I will use it until it quits or the bushing goes completely out, which could be 2 more decades. Best $40 I ever spent on a tool.  If I had not outright abused it, it would still be in perfect working condition today.