You're not going to find one so either lower your requirements or raise your price.
7" tablet with camera and no GPS is possible in your price range but 10" and camera and GPS is not out there.
Do you want/require capacitive touch screens or will resistive touch be acceptable? (Capacitive is better).
Memory requirements? 256 Meg of RAM, 512 Meg, 1 GIG?? What about internal storage? 4 Gig, 8 Gig, 16 Gig
CPU speed? 400+ Mhz, 800+ Mhz, 1 Ghz? Dual-core??
Tablets with your listed requirements are in the $399 and up range though you could possibly find a refurbished unit or even a used unit between $299-$350.
Your $150 price is 7" screen, possibly capacitive touch, maybe a camera and no GPS. Also do not expect Google apps (Gmail, Market, Maps) etc...to be available unless you can root the device and hack the google services on to it.
The Kindle Fire is a 7" tablet, no camera, no mic, no GPS, capacitive touch screen device....that still doesn't come with Google apps (needs root and hacking) and that comes in at $199.
I've been following the tablet market for over a year.
I have a relatively cheap Viewsonic Gtablet (2 of them). 10", dual-core, 1 Ghz, 512 Meg, 16 Gig storage, SD slot, USB, capacitive touch, camera...NO GPS and it was $399 at launch and now (a year later) can be found for around $250 and up used. No google apps again...but very easily one of the most hacked tablets. The screen is pretty bad....direct view is good but any angle and the image suffers tremendously.
I grabbed a Motorola Xoom off woot for $349 and a Samsung Galaxy Tab 10.1" off woot for $349. These were refurbs with your asking requirements (GPS, 10", USB and SDCard (though the Samsung doesn't have the SDCARD and USB slot).
FYI...a great app on the Market is TetherGPS ...for tablets that don't have GPS.
https://market.android.com/search?q=tetherGPS&so=1&c=apps
Install it on both your Droid X and your non-GPS tablet and if you WiFi tether your tablet to your Droid, you can also send the Droid X's GPS info to the Tablet.
Droid X runs in server mode and Tablet runs in client mode. Works great. Will also work through a home network as long as both devices are connected on the same subnet (ie...your Droid X on WiFi connected to your home router and your tablet connected to your home router).