From what I understand, you get it by being on the top 200 on the HST, so figure out how many more you need to read to reach there. You can sort the checklist results by price, select the cheapest x books to add to a wishlist, then jn will calculate the cost for you.
[edit] The lowest score is 139 and just checked wit the cheapest 140 overall. The priced items on this list would cost about 6,930,957 NP!