I solved that problem years ago by buying a studio strobe setup. It was well worth it. A good light system will outlive many cameras.
The neat thing about both macro and portrait is that you have a controlled setup and so you do not need fancy automatic TTL strobes. But what you Do need is the ability to control the light. Control both it direction and hardness/softness and the ratio of main to fill lighting. Main to fill is key in digital because of digital's very limited dynamic range.
A used studio power pack system would cost about three times your budget. but before I had this I used a set of very inexppensive Vivitar strobes and Wein "peanut slaves. The slaves are little one inch cubes of clear plastic with a "hot shoe" on top and a tripod socket on the bottom. Then I bought an Umbrella and a photoflex "softbox" then get some very cheap tripods to act as light stands. then buy the lowest priced strobe that can be aimed at theceiling and put that one one your camera. This ceiling flash trigger the other two. Total cost for the whole two light setup might be within your budget. Save money by replacing one slave and the on-camera flash with a 15 foot sync cord.
A $75 strobe inside a photoflex softbox make a realy nice light source for either people (simulating window light) or can simulate and overcast sky in a macro. My Vivitar 283 strobes are out of production but this is a replacement available for about $79
http://www.tocad.com/flash/383.html
It has enough power even for large group shots. Use it at 1/16th power setting for macros
With film I used a flash meter to set everyting up but with digital the DSLR's histogram display makes a good meter.