Heh I've missed this thread...
Oh wait this is a new one! Never mind it is still a great theme. At least you aren't trying to justify how much you spend on brewing as an offset to the family beer budget to get more money out of the deal.
Be careful about the assumption you need to go all grain to save big money. Both DME and LME can also be bought in bulk at considerable savings, and can frequently be added onto group buys for similar savings. Going all grain comes with a start up cost and I believe increases the rate of spend on equipment. For example soon you will want a better mill, then a better chiller, replacement hoses, maybe a pump, a brew stand,... the list just doesn't end. I'm looking at pH meters now... Most items after the lauter tun aren't necessary for all grain but I'm on a pretty tight budget too and the equipment expenses just don't seem to end.
That said all grain brew days are a lot of fun and much longer than extract days. For the same ingredient cost I probably get 3 all grain days for 2 extract days, and each all grain is 8-10 hours (double batch) vs. maybe 4 hours (I never did double batch extract, just guessing), bottling is the same, maybe 90 min per batch including clean-up, so for the same ingredient cost I am getting 33 hobby hours all grain vs 10 hours extract. YMMV. Plus I end up with 30 gal of beer instead of 20.