The German supplier offers the better price.
In order to compare the price, we need to be in the same currency and weight/mass unit. Right now, we're in dollars/pound and euros/kilogram, so we'll have to use the conversion factors to change units.
Let's convert euros/kilogram to dollars per pound. There is 1 dollar to 0.76 euros, so one of our conversion factors is:
We also have to convert kilograms to pounds, using this conversion factor:
We are now ready to do the conversion:
As you can see, euros and kilograms cancel out, leaving us with dollars and pounds. As you can also see, this price for candle wax is far cheaper than the American price, so this is certainly the better deal.