There are fairly inexpensive "doggy steps" being marketed in the US via TV spots (call into the 800 number). I also saw them at a target store and saw some at Target online too - $39.99 for 4 steps. As I recall, that's a little better than Fosters & Smith:
Here's the site for the product & their TV commercial. The price looks better on this site, but I'd check to make sure the shipping & handling doesn't make it just as pricey as ordering through Target:
My bed is pretty high, so I am planning to get the 4 steps for my bed and probably the 3 steps for the sofa.