your stuff looks great, the axolotl is super cool. personally i charge because it takes me a while to make, i have a couple free packs (if you wanna take a look haha) but i would price if you want to, maybe keep a pack or two free to keep some traffic going.
oh also any tips on how to make money from asset packs? ive made two dollars in the last year. any tips on advertising and stuff would be great (unless its a trade secret!)