Size 19 US and Size 50 Needles Questions on Yarn

Hi I bought two sets of Needles size 19 and 50 and need advice on how much yarn to use to make a blanket with them. I have yarn I already bought but I didn’t know if I need to buy more. I have two big skeins of mixed green yarn and thought of using two strands on the size 19 but will that be enough for a blanket? Do I need certain types of yarn for the size 50, it says on it Fun Fur and a few others that I really didn’t want, if I buy the normal yarn and put 4 strands together is that enough?

I made afghans this winter on size 17 and 13. I used 6-7 oz skeins of Carons Simply Soft which was about 2200 yards and had very little left over. The afghans were approx. 48"x66" and were knit with 2 strands of yarn.
I would think you could get away with double stranding on the 19’s, but you may want to go up to 4 strands on the 50’s. CSS is a worsted weight yarn.

Lion’s website has several patterns for the size 50s, you could compare yardage to see if you have enough. And has patterns listed by needle size so you can check out those for how much it would take for the 19s.

You can use any yarn you like on the 50s, although you might want to use a bulky weight, or as others have said, go with 4 strands of worsted. They’re just larger than anything else, so no yarn requirement, just like any other size.

where do you find the best deals on yarn? I have been buying mine at Johann Fabrics but any online stores you can recommend?

For basic acrylics and inexpensive yarns I would think Joanns or Michaels especially since they generally have coupons and sales.