First: I'm also in NE FL! Westside of Jax, to be more specific. If you live anywhere near there and are up for coffee or something one of these days, let me know. I have a 3-year-old son so depending on how old your oldest is, maybe our kids could play together.
Second: I will go about this assuming you're near enough to Jax that hopefully the locations will be familiar to you. Some of the Beall's Outlets tend to be better than others. The one in Mandarin near Goodwill (on San Jose across from KMart) seems to be consistently good. I got an Ann Taylor LOFT boyfriend cardi there for $6. The one at the St. Augustine outlets is also pretty good. We are also blessed to have several Ross stores in town. They have TONS of dresses, and cute ones at that. They have a lot of cute knit and woven tops you could try on to get a feel for what looks good on you. Style-wise, I've heard that wrap and faux-wrap dresses are almost universally flattering, and are often recommended for helping to camouflage one's midsection.
Finally, I don't know how you feel about thrift stores, but Jacksonville has some of the best in the country - maybe the world. My friends come visit often more for my thrift stores than to see me! LOL. If you can find your way to The Thrift Store (address/info here: http://jacksonville.citysearch.....store.html), you should. Bring someone over 55 with you on Wednesdays or go without them on Saturday to get 50% off everything except one tag color. The store is HUGE but there are amazing finds there! (If you're looking for layering pieces, check out their jackets. I got a gorgeous black leather blazer for $20, and a vintage blue leather trench for $25!) That is the first thrift store I take people to and usually they spend their whole shopping budget there because they find so much, so we don't go anywhere else. Depending on your kids, you may well be able to take them with you even though you should plan to spend 2-3 hours there. (I'm telling you, IT'S HUGE.) They have a decent toy section and a small section of children's books, so my son actually likes to go there because he gets to play with the toys while we're there. Also, wear leggings and a cami or something else tight under your clothes because they don't have dressing rooms. As annoying as that may seem, you really do get used to it. They have a few full-length mirrors around so you can see how things look. Also, they are cash only, though they do have an ATM near the doors. And yes, I know all that (cash only, no dressing rooms, gonna be there a while) seems like a lot of work, but I swear you could get an entire new (name brand) wardrobe there for well within your $500 budget, easily. I'll be going there this Saturday afternoon with my SIL (who saves her entire yearly clothing budget for her annual trip to visit me so we can go to The Thrift Store and Ross!), and then we'll probably be going to The Thrift Center near Wilson & Blanding intersection on Monday because they often have storewide half price sales on holidays, so Labor Day will probably be one. Then you get CRAZY deals - Ann Taylor shirts for $3, BGBC dresses for $5, etc.
Anyway. That was a lot of info, especially if you don't like thrifting, but like I said, if you want to get coffee sometime, or even go thrifting with me, let me know! And good luck with your wardrobe rebuilding!
