Well, you really picked two morphs from totally different ends of the spectrum, didn't you?
Male Pastels start around $75 as hatchlings. Female babies are going to be $100+ and adult breeders (females especially) can be a lot more. A higher quality baby will be $150ish and I've seen some really pretty female babies for $200.
Clowns tend to range from $3000 on up depending on their coloring and patterning, males being a little less expensive than females. I don't even know if people are selling their breeder clowns - their females at least. I suppose they're out there but it's going to be probably a lot more than you're going to want to spend on a first snake. It's a pretty new morph right now and it's recessive so it's going to be a lot more than a simple co-dom pastel.
But prices are really going to be dependent on the show. Sometimes shows have really great prices on really great animals and sometimes there's vendors overcharging for poor-quality animals.
Be aware that low-quality pastels will brown out very quickly. If you like the yellow coloring go for a higher quality one. Or if you like the blushing, you might want to look into a super pastel. They cost more than a regular pastel and will generally run you $500 give or take a little.
Also, make sure your enclosure is ready to go before you go to the show. You want to be able to bring your new addition home, set it down in the tub or tank, and leave it alone for a few days to a week to settle in.