It depends on if you are having a shower or not. I bought all my sons big items like the crib, playpen, changing table, carseat/stroller, swing. When we first found out the sex me and my husband did buy a few onsies and my diaper bag (since i wanted on that looks like a purse) out of excitement But everything else I got at my shower the only thing else I've bought since the shower is burp cloth, socks and one pack of bottles.
When my husband and I found out the sex we bought outfits because most guest at showers do not buy outfits. We waited to purchase everything else after our shower st 34 weeks, that way we still had time to.purchase items we did not get at the shower. We received all of our big ticketed items at our shower so we did no have to purchase anything after the shower.
I bought my big items when I found out the sex of my children. I think waiting until your baby shower can put u in a financial bind if you have your shower close to your due date even if its 6-8weeks out. If you do wait til after your shower just make sure you set one aside for those items during your pregnancy