mabel1973 - almost all of my nappies are 2nd hand, and I have no problem with that. Same as the nappies from a laundry service is the way I look at it. They'll already have been washed once since last use (hopefully ), and if you wash them again on a nice hot wash, then they will be fine.
If it does worry you, look out for some brand new ones on E-bay. I've had some that have been completely new and unwashed, and some that have been washed but never used, for lots less than the brand new price. Lots of people have good intentions whilst pg, which slip when the baby is born!
With regards to the washing, no experience with two (yet!), but I really don't find it to be a problem, and I can be lazy with normal clothes washing. My nappies just aren't in this category - they have to be washed minimum every three days. I can soon tell when the nappy bin fills up.
I have quite a lot of Tots, as I air dry them (I do tumble for half an hour though to fluff up). They take at least a day to dry, so you'd need quite a few to do this. I have 40 or so, and never ever run out. I could probably get by on 24 or 30 though. If you want a faster drying nappy, think about the rainbow bots, as these are a bit thinner, so dry more quickly.
Also, if it's not too inconvenient, hang them out on the washing line to dry. On a damp windy day, you can hang them out, and even though they don't seem much different when you bring them back in, they will dry a lot more quickly.