I used slings and never had a pram (daughter now 2.5). Firstly because I was moving from abroad and didn't see the point in buying an expensive pram (they were $$$$$ in Singapore) and having to wait months while it was shipped back. But then I got used to it, became quite the earth mother and extended feeder and had a baby that didn't like being put down - ever. So I continued with the sling, so did my husband (he looks after her on the days I work) and we never ended up buying one.
I shan't buy a pram for this one.
Really wouldn't recommend the BabyBjorn. I have used one but compared to wraps SSCs and mei tais, they are uncomfortable for both baby and mother (I think, before anyone leaps on me)
I used a Moby in very early days. Then a non-stretchy gauze (great for Singapore) then a Girasol thick non stretchy, husband liked Boba and Ergo, I have a wrap conversion but now hardly use it unless we are out and she's hanging for a nap.
Something to consider, anyway. I foudn with my daly travel (train and tube a lot), where I live (London) and the weight of my child, a pram wasn't needed or desired.
My husband actively HATES prams.