if you've not already, put a WTB in the Sales section, that may unearth someone willing to sell.
MILK cases are circa $250 themselves, add a decent insert + dial maybe another $250, then a crown/tube/crystal and then even a cheap Raffles bracelet and thats your budget done before anyones built it. Modders charge between $200 and $600 for putting these things together... you can find parts on the "parts" section and gather them yourself until you have all you need.
my 1675/3 cost me $1000 in parts alone and that wasn't an expensive build but was a MILK case/bezel .... but my 1675 I purchased m2m was more than that but also had much better quality parts.....
......as previous people mention, just hunting via M2M and you may find you manage to get a decent 1675 or 16750 that someone has lost interest in.
happy hunting thats most of the fun of this game isnt it!