Pat,
There are many combo's out there.
Two of the more common guide cameras are the SX Lodestar (
http://www.sxccd.com/lodestar-autoguider ) and QHY5 (
http://www.gamaelectronics.com.au/qh...%20prices.html).
The QHY5 is half the price of the lodestar, however the lodestar has better sensitivity (which may help for an OAG).
Starlight Xpress also have an OAG that retails for around $300, you can see it on this page (minus the FW):
http://www.sxccd.com/sx-usb-filter-wheel
Ideally if you went with the SX OAG then id get the Lodestar to go with it.
I personally don't own an OAG at this time so i cant give you much more, but the Starlight Xpress OAG is well known and probably one of the cheaper ones. Combined with a Lodestar camera and you get a great guiding setup.
The QHY5 works well, however it lacks the sensitivity of the lodestar. Will it be a problem? depends where you image from and what you are imaging. In a star desert it may be hard to find a star, thus the extra sensitivity of the lodestar is fine. If your imaging something in the 'belt' then either camera will be fine.
SX lodestar and OAG can be purchased from Claude @ AEC:
http://members.ozemail.com.au/~aeccl...ght_xpress.htm
The QHY5 you can get from Theo at Gama electronics:
http://www.gamaelectronics.com.au/qh...%20prices.html
Hopefully someone else will pip-in some suggestions.
Good luck.