If you wait for an invoice before paying, postage on combined items will be as follows:
Up to 1 yd: $2.50
1.25 yds: $3.50
1.5 yds: $5.50 (occasionally $3.50)
2 to 2.5 yds: $8.50 reg'd post
($5.50 ordinary mail if the fabric is worth less than $50).
3 or more yds in one continuous piece: $12 satchel + insurance of $1.50 per $100.
If it saves on postage I'll split an order and send it in two envelopes instead of one.
I usually post the next business day after I receive your payment but occasionally it might be an extra day.
If you pay or go through checkout for my bank details before I send an invoice, ebay will add up the postage on all the items and charge fees on the total. I can't refund the amount of the fees on the overpaid postage (around 10%) after you've paid, and with some payments the system won't let me refund any at all, so you need to wait for an invoice if you don't want to over-pay on postage for combined/multiple items. I don't refund at all for amounts $1 or less.