In Patrick Leach's monthly list there are occasionally H&R full, half and partial sets. In the May list there is a half set for about $700.
This month there is a set of 30 H&Rs listed for ~$795. My guess is it may already be sold.
My accumulation has been mostly purchased and some were acquired by trading for them. The exact number of how many are in my kit eludes me. My attempt at counting my planes ended when it got to about 60.
My best guess for my group of Hollows & Rounds is it probably set me back less than $300. It includes all but one of the even numbered sizes and a few of the odd numbered sizes.
With a pair of the same size H&R from different makers it is easy to use one of the pair to make the other conform so they are matched to each other.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)