If you don't want to spend gil and dont mind gathering your own mats, gather the mats to craft 1 star items and turn them in for seals. If you have some spare gold ore there's a few 1 star GSM bracelets that cost a couple of rose gold nuggets or gather the 3 1 star mats required to make a Madman's Whispering Rod (ALC). Each 1 star turn in is 633 seals regardless of quality and the mats are now priced at 800 seals each so it should only take you a couple of trips to the node before you have enough seals for a book.
Takes a few more than a couple of trips if you do rose gold since it's 6gold ores per bracelet, plus the basilisk whetstones(or 9gold ores if you do the ones without basilisk), and you still pay a bunch of shards/crystals. Also, you're completely discarding the value of the gold ore themselves. They generally sell at 500each, so 3k worth of gold ores, 1k worth of crystals+basilisk egg then the time to combine all of it, and that's not even enough seals to buy a 4k item on the market board(can even buy it cheaper if you wait the right time).
The alchemy turn in is a bit better, it's only about 3k worth of stuff. It's still 3k worth of stuff to have not enough seals to buy a 4k item.
Items you gather aren't "free". You don't pay money for them, but you spend time gathering them and then time to convert them into something usable and more importantly, you're not reselling them for money. That money you're not getting is the real price.