I like a one price policy, but do you have other items at other prices?
I plan to have some items that will be slightly higher, but they will be limited to anything that I find that is really special. Over all, you can expect the single price to be about 90 to 95% of the items.
Additionally, I may have items that will be less! That is not a bad thing, some times I find something terrific but priced so low (like a close out, etc.) that I will offer them as well as a reduced price.
Of course, some of the 'one price' items may go on sale as well, so you cannot lose.....