Yes, you do need to dress a little nicer for the national shows. I made a vest that I took fabric and used glitter paint to add sparkle to it. I then got new black jeans and made a bow for my hair and a tie to go with my tuxedo shirt to match the vest. For another outfit, I have black dress slacks and the same white shirt with a jacket I purchased out of the Sheplers catalog. I like basic black pants and white shirts and then jackets or vests--for my husband also.
For future reference, after Christmas you MUST go shop on the sales racks at the malls for left over holiday clothes. Glitz everywhere for dirt cheap.
If it were me, going to Nationals, I'd be heading myself off to Sears, or JCPenney, to the "dressy" section and be looking there for some serious dressy blazers and blouses and be pairing them up with nice dress pants. Look in the bridle department too for accessories.
I have to say the majority of my Nationals clothes were found at thrift stores. I just don't have a lot of money to spend... particularly on clothes!!! Most of my money goes to board, vet bills, farrier bills, grain, supplements, shavings.... sigh...
Anyway you can find some VERY nice things at thrift stores, and for cheap! My purple blazer was $4.50, my burgundy prom-type dress was $3.00... you get the idea...
I've actually found myself getting sort of WAY too picky... last week I was looking at a couple blazers and found myself thinking "This one is $8.00... it's not half off like a lot of them... that is just WAY too much..." but then I remembered my $75 blazer just doesn't fit me any more (I bought it two years ago before I lost 35lbs) and so really, eight bucks isn't bad!!!
Anyway, eBay and thrift stores... that's MY big tip for you