Have you been on the knot yet? Go check out the Las Vegas community board, they should be able to give you suggestions. Also have you looked at golf courses or a private mansion?
Try THE MEET
Check out The Grove
We were on a budget, too, and wanted to have a non traditional experience for our guests. What it took was slimming down the guest list to about 125. We estimated 50 would go, we ended up with 73 & had to move the reception entirely. The Knot LV message board was an absolute lifesaver for me! I'm certain every vendor we used was because I heard about them from another bride. Best of luck!!
I had mine at the Grove -pretty place, not too expensive, and our coordinator Zina was awesome. You can use their all inclusive packages, or build your own party. They do weddings and receptions.
Check out Vegas Chapels they have several options and a variety of prices their website is 720wedding.com
good luck. We had our ceremony at the Terrace it was beautiful.