| Buri |
I can't suggest subs because subs are subs. If you want 60% view of what's what then you need the CRB, Bestiary 1 for all the monster feats and rules, APG for those 'might as well be core' options, ISWG for setting, UE for a comprehensive gear resource, and optionally UC for all the traits. You could get the ARG as well for a thorough resource on all the races and their favored class bonuses. The rest of the 40% are from the myriad splat books and other core rule books as well as the adventure paths as several have items and spells now considered common.
| Voadam |
APs are 96 pages for $20 plus you get the 15% off everything discount. On the downside if you are not going to DM then the half of the package that is the adventure should be avoided giving you only ~48 pages of material.
The setting books are 64 pages for $20 but provide the most intersting reading material IMO. It is regional lore or topic lore which is almost all interesting and could by used by a potential player as world knowledge.
The 32 page player companion stuff is more player mechanics oriented and has less in-depth descriptive fluff than the campaign setting books.
The modules used to be 32 pages but are usually longer. Again if you expect to play and never DM then it would be better getting your reading in elsewhere.
The novels will give a ton of pages cheaper.
The big hardcovers will be chock full of stuff but can be gotten cheaper as $10 pdfs and most of their content will be added to the PSRD. The hardcovers can be gotten cheaper on Amazon than through the subscription.
Maps are neat but mostly for actual tabletop use, there is no reading for most of them.