I'm sure the 4 year old will love it - and the best thing about playmobil is, you can put it into a laundry net and give it a good wash
My younger niece and nephew got a whole lot of the stuff from their cousins a few years older and they quite enjoyed it (although they do prefer lego

)
I've got a few more things in the shed that I was going to sell at a car boot sale, but they've been in the shed since I moved here which will be 6 years in August so I may as well dig it out and see what can be given away / sold differently instead