YMMV - I haven't found this.

OP
There's a fantastic food blogger who covers Osaka. I can't imagine there's a better guide.
http://blog.livedoor.jp/osakanohonnma/
Delve through the entries (pure food porn) and use a translation tool to get the gist - it's particularly useful to be clear if the price is for a lunch or evening menu. You should also be able to cut and paste the Japanese address into Google Maps to figure out the address.
You can always print out the meal review (if it's recent) and indicate that that's the sort of thing you're after. Just be clear about the price before you finalise your order - you can do all this with sign language, restaurant staff are invariably patient and understanding (at least they'll seem that way!)
If there's anywhere that takes your fancy that you need help locating, someone here will be able to help.
BUT PLEASE REMEMBER THAT AN AFFORDABLE LUNCH TIME MENU DOES NOT MEAN THE RESTAURANT IS AFFORDABLE IN THE EVENINGS

Last year a colleague went to Osaka for a short visit and I plundered the blog for her. I concentrated mostly on highly rated great deal lunchtime offerings at but there are a few evening suggestions. Both her and her friend ate fish but not other kinds of meat and their budget was very limited thanks to a weak GBP - the map reflects this also. Anyway, here it is. LINK
The one non-fish/vegetable recommendation I included was Nihon Ryori Endo, an expensive restaurant which offers (or offered) a kickass oyakodon at lunchtime for 1,000yen