How do I find mom friends ?

I'm a 22 year old mom my son is 6 months old but he is as big as a 2 year old and he doesn't sit up yet so if I were to find a mom friend how can I initiate our babies playing together when I can't even think of how they could play together and plus he would have to play with a baby his age in order to be around the same development level as him but most babies his age are way smaller than him and plus I wouldn't know how to go about getting a mom friend I don't have money for mommy and me classes and I don't drive to even get to the free ones, and I don't want to go to a playground because it seems a bit ridiculous to take my 6 month old to a playground when he can't even play on any of the things there lol so where can I meet a mom friend ???? I'm so confused lol and what do I say to initiate a friendship or at least one for our babies.

Update: are there any moms around Nassau county Long Island on here around 22 and have a baby close to 6 months ? lol I'm so bad at this.