I've just seen that Palgrave Macmillan are offering many of their hard cover books for only £19.99, including shipping to "anywhere in the world", until 31 December 2020. They say that they have over 18,000 hard cover titles on sale at £19.99 and the sale appears to be valid worldwide, not just the UK.
Books to the UK are shipped from Europe. If UK buyers try to pay with PayPal then you have to pay in Euros - pay direct by credit card and you pay in GBP (saving a lot of exchange rate fees).
Sign up to their newsletter first, before you place an order, and you get a £5 (EUR/$) voucher sent to you!
Lots of Ethiopia related titles are available for only £19.99 each, a small selection of some of the more obvious include: