The Turf: $$
2nd Ave. and Pike St.
The Turf is very much a "greasy spoon" sort of place. It looks like the kind of place you wouldn't want to go into, with the "odd" population of the place. On the other hand, they make one of the best burgers I've had. Ever. For $6 or so. Burger, fries, and if you ask nicely, they'll usually give you some gravy to put on the fries. Tasty, filling, homecooked, and cheap. They also have teriyaki, lumpia, French dip, and make a passable fried rice - better than a lot of the chinese carryouts I've been to downtown.
Osaka Teriyaki: $$
2nd Ave. and Pike St.
Apparently nicknamed "Scary Teri," this is another place where you get some unsavory-looking elements. At the same time, you can't beat a $5.50 chicken teriyaki carryout plate - and they have beef, pork, or mixed for those who are more hungry. They don't skimp on the rice, and they toss in a cheap-o lettuce salad on top. They'll skip the salad part if you ask.
If you're not comfortable in the city, I'd warn against either of these two places. I'm not particularly worried about violence since it's a well patrolled area and the people are genuinely nice, but there tend to be some unsavory-looking people at these places. Also remember that these two places are excellent "bang for the buck" - I'm a big guy, and a meal from either place will fill me up.
The Lola: $$$-$$$$$
4th Avenue and Virginia St.
No, not the loli, the Lola. This is moving into the realm of "not sure if they'll let you in if you're cosplaying," but the food is awesome. I'll often wander in here in jeans and a t-shirt and they'll let me in with no problem. I also took my redneck dad and uncle (from the East Coast) in there and they still let us in, so I think they're not -too- choosy.

It's very much a sit-down sort of place - expect to wait 15 minutes for appetizers and up to 45 if you're getting a big meal. Recommended dishes are their pita wedges and spreads (they've typically got 6 choices - get the minty feta if they still have it!), the lamb burger (mmm. dead baby animals.), and the assorted kebabs they have. There's a bar in the place as well, and they're happy to serve you there. If you get Guillermo as the bartender, ask his advice - he's happy to give it, and he's usually pretty spot-on for recommending. Also tip him well.

Also of note is that if you go during lunchtime (11am-4pm if I remember right?), the prices are significantly cheaper - if you get the right menu items, you can easily get into $$ territory for a group, though it won't really be a "meal."
Dahlia Lounge: $$$$$
4th Avenue and Virginia St.
I've never been to this one, but from everything I've heard, it's a very formal and classy place. I couldn't tell you for certain what kind of food they have or anything of the sort, but I guarantee you that it's the kind of place you go to -after- con, once you've put away your cosplay.
Dahlia Bakery: $$-$$$$
4th Avenue and Virginia St.
This is actually right next to the Lounge, and I frequent this place. You can get a large loaf of regular bread for $4.50, the same spreads they serve at the Lola for $6 per 8 ounce tub, as well as an assortment of pastries. I also believe they sell sandwiches, but this could be a great place for a "build your own" sort of meal in combination with the next one. By the way, I personally recommend the "Pain de Campagne" if you like sourdough bread. <3
Ralph's Grocery and Deli: $$$-$$$$
4th Avenue and Lenora St.
Ralph's is a strange place. Light jazz music and a huge selection of wines, they tend to be overpriced vs. other places in town - not by a huge amount, but enough to make you pause based on whether it's convenient. That being said, they serve coffee at reasonable prices, have a hot bar that features plates in the $6-8 range (if I remember right), and an assortment of groceries and lunch meats that you can get. Also, they have a sit-down area with wi-fi where you can eat or just hang out (as long as you bought -something- there.) Combine the stuff you can get here with the fresh bread available at the Dahlia Bakery, and you can have excellently tasty sandwiches for a weekend. Of course, if you don't mind a bit of walking around town, I'd recommend going to the IGA on 3rd and Pike. They're cheaper for the groceries.
Brassiere Margeaux: $$$$-$$$$$
4th Avenue and Lenora St.
I've also never been to this one, but it looks as classy as the Dahlia from outside. The menu is posted out front, and the prices seem quite reasonable - it's generally French cuisine, and they've got some seafood dishes kicking around there as well. If you don't get too fancy, it seems like you'd get in under $30 a plate, but you've got to figure in tax and tip - that might push it into $$$$$ territory.
Kress IGA: $$-$$$$ (already on list)
3rd Avenue and Pike St.
Another of my favorite lunchtime destinations when I was working at the downtown Office Depot, the IGA has a good deli area and a hot/salad bar, as well as the assorted groceries available. They also have a teriyaki/sushi place inside, though if I ate sushi, I'd be leery of something that's in a refrigerator case. It seems like the chinese carryout style food doesn't keep well in those trays. I'm also not sure if you can get them to do rolls custom for you - it may be something to check out. Picks from this place are mozzarella sticks and chicken strips (which will run you about $8-10 if you get 10 sticks and 4 strips), and the assorted things from the hot bar. Ask the deli people how long it's been since the bar was stocked - they're usually cool about it as long as you're askin' nicely.
Chipotle: $$-$$$
3rd Avenue and Pike St.
A new competitor to Qdoba downtown, Chipotle has a similar "assembly line" style for ordering - you choose your dish, toppings, and accessories as you move right in the line. You can usually get out of here with a burrito, chips, and a drink for about $10. The food isn't bad at all for "Mexican," and it's nice and filling.