One thing I did to save money with my second baby was to use Parent’s Choice diapers and formula from Walmart. Of course breastfeeding would be even more frugal but I could not because of medication. Also if you have a good thrift store in your area for clothes, maybe even baby furniture but the crib needs to be made in recent years for safety standards.
Also make your own baby food. Don’t buy babyfood applesauce. Nonsweetened regular applesauce is just as good.
That is all I can think of right now. Oh you could use cloth diapers too.