I only started collecting USD notes within the last few months but from my limited knowledge:
Unless they're super radars ABBBBBBA etc they are not really valued to highly. I scratch my head and wonder why considering USD notes have 1 extra digit meaning the center number MUST be doubled for it to be a radar AAABBAAA, hence they are harder to come by.
In general Radars, unless super, aren't too hard expensive to get. I offered a buy-it-now of $5.75 with shipping included and it was accepted within 5-10 minutes. (G17599571B)
Even two digit radars aren't really prized. Ive seen quite a few at buy it now $20-25 range that have been running forever without any buyers.
Another odd thing is that collectors of american notes really love their broken/partial ladders as well as their binary numbered serial numbers.