Hi Maureen
I started buying lots like most people but then started buying them indivdually quite early on to get the ones I didn't have. I bougth a lot from a seller named bulldogsbonkers and would keep refreshing the page when he was listing so I could buy the ones I wanted before he listed the next smurf about a minute later...lol.
I still mainly buy individual smurfs but if I do end up buying lost then it's sometimes very handy in finding variations as a surprise that you weren't expecting.
However big lots tend to be too expensive for me now as I am chasing variations that i don't have and the markings are not often listed in big lots. However I will attempt to buy any smurf whether it's online shops, ebay or via private sales if it's something I need. They all tend to work ok most of the time.
Dyar