Follow-up, more specific request for suggestions
You have now learned that in Philadelphia, reservations are essential at some of our best, small BYOB's. For places like Django and Pif, you sometimes need to call weeks in advance.
I'll add a couple more to David's suggestions:
A good little French bistro is La Boheme, at 246 S. 11th St. It is BYOB and I think it is cash only. Phone is 215-351-9901.
Next door to Vietnam, on N. 11th St., is a tiny and terrific Chinese restaurant called Lee How Fook. If you can get in (try early), it's nothing exotic or unusual, just very good. We will be there tonight if we can get in; otherwise, we'll be next door at Vietnam.
If you want to go farther, Nan, a short bus or cab ride to 40th & Chestnut, is marvelous. It's French/Thai, BYOB. It's hard to get a reservation, but sometimes there's an opening. Phone: 215-382-0818.
in the realm of Asian cuisine you might want to try some of the Vietnamese restuarants in chinatown. There are Vietnam (where we'll be tonight), Vietnam Palace (both on N. 11th St.) or Pho Xe Lua on 9th and Race. There are also Penang (Malaysian) and Indonesia Restaurant as well. You can eat authentic food in Chinatown for next to nothing.
For good BYOB cafes, there is Chloe (2nd and Arch) and one of my favorites, Overtures (5th and Passyunk), and Figs (French/Moroccon) near the Art Museum. For great Neuvo Latino food there are Azafran (3rd and South), Cibucan (21st and Sansom) and Tierra Colombiana (N. 5th st. in North Philly).
Your choices are unlimited. I have eaten at Brigid's and would say that they offer fairly good food at very reasonable prices in a nice neighborhood. There is also Cuvee NotreDame as well in that area for Belgian food. Enjoy! David