I don't know if you would manage cheaper, tbh. A pair of long sleeved jersey pyjamas for me, a shortish size 12ish, needs 3m of fabric, even if it's plain.
Single jersey, French Terry and even swestshirting all curl to some extent, eveninif good quality simply because of how they're constructed. Interlock and rib (not cuffing) don't curl but, aside from being harder to get, make for less comfortable pyjamas. Rib would work for a top but not so well for bottoms as it tends to cling.