Anyone know - can I use a cheaper yarn?

Most yarns have a bit on the band that tells you the number of rows and stitches for a tension square with a given size of needle. I use this to find a yarn which will knit up in a similar way, and I always do my own tension square before starting.

Marelli There should be no problem as long as you use a similar thickness yarn. I have just looked at the Debbie Bliss site and her yarns appear to be sold in standard UK sizes.

Try another yarn in the same gauge, and sneak a look at what tension is given on the original Debbie Bliss yarn wrapper and work from there. Often just adjusting the size of needles should do the trick.

The weight of the yarn and the length per ball is given on the band wrapper. So 50gr of a heavy wool yarn will probably have less length that 50g of a lighter weight yarn, so you might need more or less of one sort or the other very complicated.

An assistant in a good local wool shop explained that one to me and saved me buying too much.

Try the wool warehouse or the sheep shed for good price ( cheap) wools with free postage over certain amounts.

I've had a look at the Wool Warehouse - really impressed (not advertising)! Thank you everyone for your tips.

Marelli Black sheep wools often have offers on Debbie Bliss yarn. Just google them or look for them on Facebook.