You might be surprised how cheap you can buy a used radio for your Camry on ebay and make it worth the switchout since you'll likely have to pull the unit in the first place. I have a factory '99 Corolla cassette radio I just pulled to do the aftermarket thing with and I'd let it go for $20 and whatever USPS charge there is for the small flat rate box. Not sure if they'll interchange, but I could check with my neighbor as she has a 94 Camry.
Our 96 Subaru Legacy was easy to upgrade with their later model radio/ 6 CD changer(DIN 2). Found three of them either on NASIOC.com or ebay for $50 each. Maybe the TN for sale page might be as kind to you.
The switchout for the Corolla required a stiff putty knife to GENTLY pry the dash cover off, a Phillips screwdriver, and a ratchet w/8mm socket to remove the brackets from the radio and transfer them to your new unit. The back is pretty much plug and play and installation the reverse of removal.
"What's another word for Thesaurus?"- Steven Wright