The problem with precuts is if you wash them some shrink uneven.
I do not wash them now.
Also only buy them on sale cheap.
They are fun to sew with and you get the whole fabric line to play with.
Connecting threads is great not only because of cost but you can choose which fabrics to buy by the yard once you have seen them and know the colors you want are true.
I also buy charm packs by 3s if I really like the fabrics.
One pack dosnt go very far.