To clarify, Wild West charges $6.75 plus 25% revenue share that is above $6.75.
Per their FAQ, the transaction and credit card fees are 2.5% plus .25 per transaction (so if a customer purchases 50 domains in one transaction the fee is only $.25).
Therefore, if a reseller charges $8.75, then the buy rate is $6.75 + 25% of ($8.75 - $6.75) or $6.75 + $.50 = $7.25. The credit card fee equals $.22 ($8.75 x 2.5%) and the transaction fee equals $.25. So, the total buy rate equals $7.25 + $.22 + $.25 = $7.72. Therefore, charging $8.75 the margin equals $1.03. Only 100 domains nets you $103 per month which is much better (30%) than the enom example posted above (plus a lower price).