On this page I detail a way to make a simple "guidescope" for astrophotography from a cheap Meade 8x50 finderscope. These finderscopes can be bought used for around $40, and are easy to convert to a guidescope.
UPDATE: I finally had a chance to test the "finder guider" out. It worked as expected with one important note. I had a little trouble getting PHD to calibrate on a guidestar, presumably because the finder guider has a wide field of view and because the mount I was using (CG5) has a lot of backlash and movement in it. I was trying to guide on a star that was quite near the north celestial pole, and even setting the PHD calibration step to the max (10,000) PHD still couldn't calibrate because the star didn't move enough. So I went to a star further in the east and away from the NCP and this time it calibrated in about 25 steps. So in order to use this guide scope and PHD, I'll first need to calibrate on a star in the east (or west depending on the object I want to image).
1. The eyepiece end of the finderscope unscrews from the finderscope tube.