Ubercart

If you are looking only for two prices solution for EVERY product, then you could try Alternative Prices module. You can modify the basic price by PHP equations - so its simple to use. And the resulting prices are reflected in cart and checkout too.
But if you are looking for some more robust solutions, then I think the use of "stock prices" in combination with Views are now the best one.

I've been doing quite a bit with the uc_discount module in the last few days, and it works great for what I need to do, for the most part. My particular situation is that I have a client that runs a regular end-user store that also allows for B2B transactions if you are logged in as a wholesaler. So I don't want to use discount "codes" (like uc_discounts_alt requires), and I want discounted prices to be displayed across the site as if they are normal prices. So once a reseller logs in, they see the same product catalog, with prices set to 50% of retail.

uc_discount works great for that, but there's quite a bit of trouble with interoperability with other modules that I've run into. The biggest problem is that uc_discount relies on hook_uc_price_handler to alter product prices, which makes perfect sense, but a lot of other modules don't call uc_price when they do calculations. A lot of the time they just call uc_cart_get_contents, and then sum up the cart contents directly from the cart items. That means that any shipping module that quotes shipping based on order total (such as uc_tablequote), or the uc_coupon module, don't get the updated order total based on product discounts applied by uc_discount. I've modified these modules to use uc_price with a context that will fire the CA trigger in uc_discount_price_handler_alter, but this is obviously not a great solution.

So it seems like there should be some low-level hook allowing you to stack up price modifiers that get applied every place that a price is requested, or that prices should be modified before they get added in the cart so that once it's in the cart it doesn't have to get modified every time you want to display it. This seems to be the idea with hook_price_handler_alter, but it's too easy (and too commonplace) for other modules to circumvent it. Plus if I want to do something like display a cart total on every page, I have to make sure that I set up the correct context for uc_discount_price_handler_alter to do its thing before I call uc_price. This means lots of unnecessary node_loads on each page. A better solution would be to just generate a cart total and store it in the session when a product gets added or deleted, so I'll probably end up doing that eventually.

But these are just the results of a couple days of hair pulling . This is my first large-scale site with Ubercart, as all of the others have been pretty straightforward web stores with small product catalogs. This is also my first site with v2, so if my comments above are way off base, please let me know. I'd love to be wrong!