Ok, if you have around 1000.- costs alone, the organizational effort, especially a day off work!!! and only save 500.-, then I wouldn’t do it either. However, I wonder why it was so cheap (no basement???). The material is also needed by the excavation contractor and at least two men plus machines for one day. Two men plus machine rental for 500.-€ is really a super bargain, which is probably more of an exception.