Funny enough I recently bought an N100 Mini-PC with 8GB (as a Christmas present to replace somebody’s aged Windows 8 PC) for just a bit over $140 (more precisely €123, so $143 at today’s exchange rate).

According to this the performance of the microprocessor on the Pi5 is at the same level as that of the N100.

So basically if you buy a Mini PC with an N100 and 8GB memory you can roughly get the performance of the Pi5 at the price of a Pi4 with 4GB.