OP - the most important thing you do is check if you can afford the mortgage repayments before you try and go ahead with the purchase. No point getting parents into trouble as well. If you can't afford it then really you shouldn't buy it. How much will the bank lend you on one income? You could maybe renegotiate the price with the builder down to this level. How much are apartments currently selling for in this estate would be a good place to start in your negotiations? You really need to do the maths.