Another option is a scan gauge ( www.aeroforcetech.com )
You may be able to get a better price from www.tonemonday.com
A little more than your upper budget, but way more useful than a "read only" device. Displays any two available parameters, able to read, store, or clear codes on the fly.
Also available in different color combinations.
And NO, I'm not a salesman, just a satisfied customer.
The only problem I've ever had with mine...the display doesn't come on in below freezing weather. <img src="/forums/images/graemlins/confused.gif" alt="" />

Larry W - 99 VX s/c
3" lift w/trimming & BFH mods, rollin' on 33/12.50x20" Nitto Mud Graps. Indy 4x h-d tie rods, lower links & a bunch of other stuff that put the hurt on the wallet.