@Miri531 wrote: How long does it take to receive a cleared payment via gumtree through PayPal?
That depends on whether the payment is an eCheque, an instant bank payment.
Also, if your payment is subject to PayPal's funds availability hold due to being a new seller or change in selling activity or unusual/high risk transactions, the funds will be in your account and is considered yours but temporarily unavailable for use for up to 21 days but you can do certain tasks to release the funds sooner like shipping item to your customer and either marking order shipped or providing tracking number (optional) so PayPal system can confirm delivery with carrier or customer confirms receipt of goods to release the funds.
@Miri531 wrote: How long should I wait until I post an item upon receiving payment?
You can wait 7 days from date of receipt of payment unless otherwise informed by you to the buyer for situations like (you ship once a week, custom made items, holiday/away from office, etc.)