If you are going to be by FI, if you walk down a few blocks, along the Benjamin Franklin parkway you will hit a TGI Fridays.
If you are looking for Italian, I like Bistro Romano on Lombard street. Now budget friendly can be wide open. You say you like steaks. There are great steakhouses in Center city but I would not call them budget friendly.
Maggianos is a chain restaurant that serves Italian "family style". meaning you order one or two plates and they are huge platters meant to share.
You're also not too far from South Philly which has a ton of Italian spots through out. I like Ralphs on 9th street.
Bang a left onto race street and you're in the heart of China town. Once again chinese places left and right. I haven't eaten in china town in ages so can't help you with a specific one.
All this is an easy 5-7 dollar cab ride from the franklin institute.
http://www.ralphsrestaurant.com/
If you want a ton of choices, head over to reading terminal. warning. It is always crowded in there especially on the weekends but it's extremely budget friendly.