Absolutely not tacky at all. I can't imagine having even 18 people to buy for, and fortunately for me, it's just my brother, son and DIL, and 3 grandkids - and of course the poochies! Even so - it's more of a strain every year - retirement pay sucks and so does the economy.
Do what you have to - and please don't feel guilty about it. Christmas has become way too much of a commercial venture, and the true meaning seems to fade more every year. So sad!