Youngest you’d put baby in stroller w/out car seat?

JK

I was able to get a double Bob off market place for a good price & am super excited about it! But I’ve been trying to get the attachment for my car seat & having a hard time finding one for a decent price (not really wanting to spend an extra $75-100). Trying to decide if I need to bite the bullet or if I can make do without, until I can just put baby in the stroller on his own. (I could just baby wear if we get out early on) Thoughts?