Ikea and Bedding Issues

I'm making a trip to Ikea (land of furniture we can actually afford) in November courtesy of Boo. However I'm having some bedding quandaries and need help from experienced moms. Let me see if I can explain this. Lily will be sixteen months when the new baby is born and will probably still need to be in a crib. So I plan on buying a crib for sure. However this is where it gets tricky because somewhere around six months after that Lilybug will be close to two, Baby girl will be close to 6 months and we will be bringing home Baby boy and he could be anywhere from 1-3 years. I want to get the bedding taken care of in this shopping trip, but do I get a crib and a toddler bed? Are toddler beds even worth the trouble for a bed they can only sleep in for two years. Would it be crazy to put a two year old in a day bed with rails?

Or do I just buy two cribs and become a three crib household and just covert them into toddler beds as needed and worry about bigger beds in three years?

Of course money is a huge factor, and will be in the foreseeable future as well.

Help!