I have never bought a new tank, alway used. I try to buy from members of my local reef club, generally a little better experience over random person on marketplace. that said my last 2 were off market place. both killer deals.
125g 6' tank stand, canopy, sump, 3 g4 xr30s, 60" t5, 150 lbs dry rock, 57w uv, magus 7 skimmer- was $500
This tank is currently setup and running,
I am upgrading to a 300 which i recently bought. this one needs a bit more work
300G shallow 96x30x24 tall, 125g sump, no stand(was a built in) 3 nib skimz l160 pumps, skimmer, 140g frag tank, 45g frag tank, was a huge bundle deal -$1100
deals can be had if you don't mind some work. I would not be in this hobby if I bought new.
My $500 125g