I have not found lamb burger to be commonly available at most grocery stores and when offered, the cost can and may raise an eye brow. The additional challenge is creating and cooking a lamb burger that knocks the socks off your guests. When they respond to their first bite/taste and say, "Oh, my goodness!".
I certainly do not claim to have done this without some professional help and please let me explain.
Hapanowicz Brothers in Utica, New York is a 95 year old butcher shop that offers six large lamb burgers for less than $10 dollars. Really twelve burgers because they are so large. We split them in half and reform the patties. The cost per pound is less than four dollars. Ground fresh. So, we have the supplier of affordable ground lamb.
Not too far away from Hapanowicz Brothers is Symeon's restaurant, a Greek restaurant that has been in business since 1973. Their food is truely amazing. Here is where the magic comes into play.
I buy their dry seasonings, a large jar for less than $6.00. I also buy their yogurt dressing they serve with their lamb skewers. I take them up the mountain, grill them and we devour the finished product. Cooked rare of course. Pick your own cheese of course. We prefer Swiss. Yogurt condiment or mustard or even the blend of both condiments is wonderful. Of course a sprinkling of their dry seasoning. As an aside, with their dry seasonings, think rub, they provide recipes for their salad dressing and marinades. These are dynamite.
Hapanowicz Brothers www.hapanowiczbros.com