Being thrifty doesn't necessarily mean being frumpy.
I mean, a ton of girls with lots of money frequent thrift stores because you can find gems of clothing there which you wouldn't stand a chance finding in regular stores. You just need to spend a bit more time in there rooting through stuff and you'll find something which will look great on you; and a lot of classic things in there too.
People buy things in fashion, and get rid of things when a new trend comes along, and some of these 'out' trends are pretty timeless and can look great.
guys care way more about your face, skin, hair, and body than you clothes.
having said that, you need to wear things that make you feel good. get online and spend some time looking at vintage, thrift, and second hand style sites to get some ideas. you can still find clothes that fit you well and show off your better traits for a couple bucks.
but be yourself. wear what you like. you want the guys you attract to match your personality and style.
you can still be stylish wearing cheap clothes, you just have to know what to buy, how to accessorise & wear it. too many women in their 40's write themselves off because they think that no-one is looking at them or that they're not young or trendy enough.
dress for your shape not your age, weight or income level and you'll do fine. I was piss-poor for about 8 years after being quite well-off most of my life and that was the biggest shock of all (excluded from shopping). If you have to make-do with charity shops & clothes swap situations, then go to more affluent areas to find the better quality stores - believe me it is possible.
You don't have to have money to look nice...I don't have money either. It's called clearance racks and sales.(: My friend gets all of her clothes from thrift stores and EVERYONE compliments her, it's pretty cool.
I'm real "money challenged" as well and The Salvation Army is one of my favorite stores! If you have one nearby(which you probably do), you should check it out. It looks dumpy and everything there is second hand but the clothes are dirt cheap. Almost all of them are in great condition and fashionable too. I constantly find expensive label clothes that STILL HAVE THE TAGS ON THEM. It's like rich people drop off things they don't like without even wearing them first.