Annoying isn't it!

I used to write back saying.. 'Sorry, I was after payment in magic beans'

If it wasn't "how much for cash?"

The other favourite would be an offer around half the asking price (say car was well priced at £10k) You'd get.. "Would you take £5,000 CASH?"

Note the cash in capitals!

I used to sell the odd car on eBay. I had my mate's modded Evo 8 on there, he paid £18k for it (was a fair few years ago) and they were around £16k when he wanted to sell. I had it on eBay for £15k which was below average and it was low mileage and lots of expensive bits. I had the best offer option and some of the offers were hilarious. Some twat actually offered £3k. Now, I assumed he was joking but replied with a reply along the lines of "why are you wasting my time with silly offers?" And he actually wrote back saying "well, you might have been desperate to sell"