[Ender_Muncher]

Most small shops base their shop prices off of the larger shops on the server. Those prices are usually based off of supply/demand of an item, how common it is, and some prices of items are based off of the prices at the server shop, /warp shop. As far as I know, there isn't a list of suggested prices for items, however some items have a "standard" price you'll see across all shops, such as diamonds selling for $50 each or $450 a block. You can certainly base your prices off of larger shops if you desire, or set competitive prices compared to those larger shops; it's all up to you.