All subject to veto by
@Hoyr, but: Our security guards are being paid 350,000 per quarter per team of 20. That's 70,000 credits per year in total compensation and, since it's fairly universally true that 1/3rd of total compensation usually goes to non-salary benefits, that translates to roughly 46,666 per year in salary. This is, incidentally, equal to the salary of the highest paid security guards in the USA, leading me to conclude that the credit in our games is roughly at parity with the modern US dollar.
Given that, you can use prices in the US to get a rough idea as to what things should cost in the ME universe:
5-10,000 for a decent used car
15-18,000 for a new compact car
20-25,000 for a new midsize car
65,000 base price for a Tesla Model S (85,000 for a fully-loaded one)
Property prices vary
extremely widely based on a number of factors (location, school district, etc), so it's rather hard to give a meaningful price range for them.