Jeremy - I've got some very nice older Millers Falls, Record, and Bailey planes. Very few of these was much over $50, many were $20-$30 if you catch the right one. Generally $40-$60 buys a very nice example of these older planes, and they work great.
$20 can buy a good one if you're willing to clean it up. Most of the older planes have been fettled at some point, so there's really not a lot of work on many of them.
Can't say as though they're comparable to a LN but they work well, have excellent machining and metallurgy, and are worthy to be passed on to future generations. I'd think a #3 smoother and a #5 or 5-1/2 jack would allow you to do a lot of handwork. A #4 is always pretty universal too, but isn't as good as a jointer as the 5 or 5-1/2. Since you've got a block plane...if I could only get one, it'd be a 5 or 5-1/2 for me...the 5-1/2 is the one I reach for most.
MF #08, 09, 11, 14 (Stanley 3, 4, 5-1/4, and 5 equivalent):
Record 09-1/2, 03, 04, 04-1/2, 05, 05-1/2, 06, 07:
Bailey #5-1/4, late type 13:
MF #18 (#6 equ):
Record #04-1/2 (this one was more like $85, but is mint