I don't really understand how people are getting the price for enchanting armor. So far what I think is you have to enchant the armor to desired ability level and then buy that on its own level. Maybe this is how my group has ruled it but this is what I have so far.
I have bought enough materials for half the cost of Stoneplate (1800gp) which would equal 900 gp; this is room for failure. I make it Masterwork (150gp). So far my cost is 1,200gp for the making stoneplate armor from scratch. Now this is where it gets confusing for me.
What I believe is I have to enchant the armor to +3 to be allowed to get the wild enchantment to the armor. I have Craft Arms and Armor feat. So everything should cost 1/2:
+1 (1,000gp) would be 500gp
+2 (4,000gp) would be 2,000gp
+3 (9,000gp) would be 4,500gp
The total would equal 7,000gp. The Wild enchantment is a +3 armor special ability that costs a +3 bonus. I interpreted it as paying for 9,000gp without it being halved while casting baleful polymorph as a druid of the appropriate level.
This is leave the total cost as 16,000 gp after everything with the feat.
I am almost certain this is not the official rules for the cost of what I want so I am hoping someone can help explain this simply and discuss this with group to see if they want to go offical or keep this homerule.