What's the accepted way to add different prices to commerce products? The standard model for an e-commerce system is to have an RRP price and sale price (and when relevant a cost price).

I know there are product pricing rules to apply discounts, but this is a pretty un-intuitive solution as it requires the adding of a new rule for every single product that needs a discount. 

Plus 'discount' isn't the right way to look at this particular situation conceptually in my opinion. I don't want the users to have to work out what the discount should be when all they want is to set a static 'special offer' price. It also doesn't make sense to refer to the cost price as a discount of any kind.

What I'd like to have is 2/3 (or as many as I want to be honest) different price fields on the product to represent the different prices. The system would then obviously display the correct price at the correct time based on some sort of rule.

I know I can just add new fields to the product bundle but their relationship to the overall price of the product will obviously not exist until "something" happens.

This seems like a pretty standard use case...has anyone come up with a good solution? Code and UI solutions both welcome.
As mentioned you can add new field to your product type:

Next enable commerce_product_pricing_ui module or just add new Rule on event “Calculating the sell price of a product”. Rule looks like this (full size):

You can control the order of Product Pricing rules by Rules weight.  

But I prefer to create field “Old price” (or “Common price”) and to add simple description:


  If you want to create special offer for this product, please, place new price in the Price field and move crossed out price to “Old price” field. 


So, “Old price” is only for theming. It works for small commerce sites and I don't need any crazy Rules.