Menards has the 6X6 10-gauge rolls as well, but they and all other bigger retailers have the rolls for around $150 each. I have made a bunch of calls on trying to find some more and finally found a source. I would check with local lumber stores and farm stores. I have found a few for as low as $85 each.
If you wanted to buy 16 or more rolls, you could buy direct from a manufacturer for cheaper. I found OK Brand Wire and then contacted some of their retailers for pricing and availability. In hindsight, I wish I would have just gone together with someone else and bought in bulk. I've been told the tariffs are to blame for higher costs. You need to get lucky with finding someone using older pricing.