Free: Contests & Raffles.
Don't save money on a spotter. Save money and buy the best, you won't regret it. I went through a few low to mid-range spotters and finaly saved my money and bought a Sworovski. Wish I would have done it years ago, a lot of money, but worth every penny. If you use a spotter to hunt with, you are severely limiting yourself if you have anything else.