Actually what I would do if I was REAL short on money and I was positive the current motor wasn't fixable would be to buy a bad motor needing a headgasket or such for practically nothing and put a head gasket on it. I have actually done this
If I remember the whole process it involved the follow cost wise.
$80 in beer (help has to be paid)
$5 diesel for the tractor to pull the motor and install the motor
$50 gasket kit
$70 cigarettes
I think that was everything. We used the head off the motor with the busted block