I don't have any nursing tops or bras (well I have the bras but don't use them). I have a nursing drape if we're out and I just hike up my shirt. And flop my boob out of my now favorite bra (la senza sports bra). The only reason I use the drape is because I'm a bit self conscious about the 'extra' I have from pregnancy.
I have one nursing top my mom for me, I've never 'used' it for nursing, just to wear.
So if you don't mind destroying a comfy bra and letting your belly show... Don't worry about tops and bras. Maybe a cover js all I really worry about.