So called "free" postage killed my sales, made my items less competitive and discouraged buyers from buying multiple items, or led to problems with buyers wanting/expecting a discount, but me still being charged the eBay fees on every dollar.

I tried it for 12 months and it was terrible.

Once I got rid of it, sales improved a lot.

I still offer free postage on some more expensive items, but the majority now have postage as an addition.