When buying pantyhose, do not let your vanity cost you money!
Unless you have legs like matchsticks, buy the largest size.
Pantyhose are never baggy, even if you buy 2+ sizes larger than you are.
My height and weight would usually put me at a Size B, but I buy Size D or sometimes even Q.
Trust me, you'll be much more comfortable, and you'll be spending less money on pantyhose.
The less skintight they are as they stretch and bend (and I stretch and bend them a lot chasing after a toddler) the less likely they'll be to get runs and holes.
The less the fabric gets stretched out, the more sturdy they'll be to withstand multiple washings.
I have not bought pantyhose in over a year. Granted I usually only wear them once a week to church, still that's a lot of wearing over a year.
That store clerk will only have to look at you to know you're not the larger size, and even if he or she gives you the fisheye, who cares?
You'll save money in the long run.
Oh, plus, you should buy and wear tights instead of pantyhose whenever you can!