I'll break it down for ya.
6 lbs of two row (if you buy a 55 lb bag for about $50 that is just about 90 cents a pound) So that would be $5.40
3 lbs of rice (Practically free, a big sack of rice from the grocery store for eating, maybe 20 lbs is about $8.00) so lets be generous and call it $1.50
1oz of pride of ringwood hops if you buy it now is fairly cheap as the australian harvest just came in so for sake of argument lets call it $4, I purchased a few ounces for about $2.50 an ounce a few months ago.
A packet of dry lager yeast is less than $2.00 ( you will want to make a starter, but it doesn't have to be huge, so lets use some dme and water lets cal this an additional $3.00) If you wash yeast or pitch onto a cake like I do there is no cost.
5.40+1.50+4+5 = $15.90 if you buy everything. If you wash yeast and had purchased extra hops last summer before the shortage, your cost would be even lower. I have hops in my freezer from last summer, that cost me $6.00 a LB!... If i used those the cost would drop down to less than $10 for 5 gallons.
Essentially if I really wanted to get technical, I don't use a lot of star-san when brewing maybe twenty five cents worth and as I rent water is free. So essentially it is possible, you just need to know how to do it.