We have had some friends that started with mattress on the floor and did that for six or so months while the kids got used to not rolling off. And then they transitioned to the bed. If you tried that it would ease the shopping burdren and spread out the expense . . . you could get mattresses now and then bed frames later.
My DS's crib has a feature where it converts to a semi-enclosed toddler bed with one open side so we have been doing that. But, I will probably end up getting him an ikea hemnes for the underneath storage. If I don't do that I will get headboard only - - I actually think that the full bed frame makes rooms seem smaller and we are dealing with small rooms/limited storage.
ds 2007
dd 2010
baby dd 2014