I guess it depends on the viewing experience you're looking for, but I
recently received as a gift a 5" black and white set that my Mom picked up
at an Ames store for something like $10! I think it may have been 15 or 20
with a rebate, but in any event the price was right.

It runs on AC (with an optional adapter), batteries, or 12V.

We fired it up on a surfing trip in the Syncro Westy recently and if we set
it on the front table, it was quite viewable from the lower bed.

Just a thought...

--Bob, KE4GDC
89 Westy Syncro GL