Take a look at the steak special at Ellis Island (on Koval Street).
Not a gourmet place at all, but their steak special was $6.99. May be more now?
That's about as "budget" as you can get. Check out some of the review sites then decide for yourself.

Also, it's located on Koval Street, behind the casinos. There has been some construction going on in the area, so may be congested.
If traffic is OK, it's not too far from UNLV.