Add a way to enter a price and have it multiplied by 1.1

[SammyDelanghe]

When adding a product, it is nice if you don't need to calculate the markup price with the added 10% by hand, but it can be done automatically. It should still be possible to set a price which won't be multiplied.

[redfast00]

Would you store the original price and a markup field (defaulting to 10%) or just store the price? The first is nicer imo, but will also break the API if we're not careful.

[RealFoxie]

I would not keep the markup field, but just include a handy frontend change.
As the 10% is not super fixed, so that way the price can be rounded to something nicer too (for example 0.94 -> 0.95)