The women in Khan's crew (from Space Seed) were dressed quite fashionably, I've seen open mesh club wear that looks somewhat like this, the women in the picture is actually wearing very little. No offense, but the girl in your pair would need a certain figure to pull that costume off.
Price wise they tend to be across the board, you might luck out. Check out places that sell club and disco outfits. You could also have one custom made. I've had good luck with seamstresses who work out of their homes, prices are really about what you'd spend in a store. Take the picture to one and get a quote.
The men's clothing look to be easier to obtain, a nicely fitted red jumpsuit, not overly snug. Add the trim pieces yourself (or again a seamstress). Phaser optional.
The costumes from the movie TWOK are just your basic "road warrior" crap, there's not really much distinctive about it. Regardless of how accurate you make it, you're going to have to tell people who you're dressed as. But that kind of goes with a lot of costumes at conventions.
Whichever way you go, post pictures here please.