If you can really use fleece pants as a cover...good price

Mystery2B

Old Navy has fleece toddler pants on sale for $3.75/pair in store. Regular price is like $12.50. The store I went to had tons (like full racks of different colors, just just a few on clearance).

I've only tried this a couple times at home, but I always see people posting about fleece covers, so I don't really know why they couldn't be used as longies. 

kimilane

I tried them once over a Goodmama fitted and had a compression leak on my floor within 30 minutes. ={ I was really hoping they'd work for us, but I prefer the "guarantee" of a PUL cover or the ability for wool to absorb any wetness that I don't get to right away.

ElloPoppet

I got $4 fleece pants from childrens place and had a nice compression leak right onto my stomach in about 10 minutes (just holding him, not even in the ergo). I can see it working on a walking child, but for now they're not a standalone cover for us.