You're probably aware of the major courses around HH and as you say they are expensive. If you can go with a member there are reduced prices for guests but I'm not sure what they are.
You do have some choices a bit further afield though.
Tannarat in Pranburi is an army course. 18 holes, some of them pretty challenging. That's about 1,000THB incl caddie (if I remember rightly). It's about a 30 min drive away. I did hear just a few days ago that it's dry at the moment.
Kaeng Krachan is a great course. 27 holes. The C or Mountain 9 is always in top-class condition condition. You'd be best to combine that with either of the other original 9's, Lake or Valley. I'm sure they're back to doing their discounted Sports days again which are on Tuesdays and Thursdays. Price is 800THB incl caddie. It's about a 45 min drive away.
Around Ratchaburi there's Dragon Hills and Royal Ratchaburi. Both are excellent courses. The former is 760 THB incl caddie, the latter 740 THB. Dragon Hills sometimes do promotions and costs can drop to the 500 THB mark incl lunch. I don't know if the promotion is running yet this year. There's a third course - Panarangsi - which is military and supposedly good as well. I havn't played there yet. That, I believe, is cheaper than the other two. Journey time to all three is about 1hr 45min.
So, you'll need transport which is going to hike the overall price up, but there is good value for money out there. If you go to Ratchaburi, think about hiring a car for a couple of days and play Dragon Hills and Royal Ratchaburi. You'll find more than adequate accommodation for next to nothing up that way.
Here's a link to the above courses -
http://www.tourismhuahin.com/golf-huahin.php - with contact numbers so give them a ring and see what they're offering. I don't think you'll get discounted days at the main HH courses.
Sea Pines is also worth a look. Again, reputedly in excellent condition and a good test of golf. About 20 min drive. Note, I think the prices have gone up to about 2,000 THB incl caddie now.
Have fun.