I have downsized to a 21 litre batch now that I have a brew bucket.
Generally around/under $20 for a low-hopped ale, recycling previously acquired yeast (some from the lhbs, some from friends or case swaps). American blonde, German pils/ Helles, American wheat are cheap enough.
The cost can/will double (or more)with a huge hoppy IIPA, despite the good prices from my lhbs (they know who they are).
So, it can be done for under $1/litre.