Reddit mentions of TOPHORT Inline Duct Fan GDF100-4inch 203CFM Ventilation Fan HVAC Exhaust Blower Replacement for Grow Tent … (4 Inch)

Firstly, welcome to the club!

You're absolutely right - buy the accessories and consumables elsewhere. FSL don't make these and are having to mark up things due to providing a warranty and service.

Here's a good quiet fan that will do the job and is a legit 200CFM (a lot of them lie about capacity).

https://www.amazon.com/gp/product/B07FVTGB4C/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

It does come with basic optics which will be fine until you need to replace them in a few years.

You'll need a bucket and some tubing for the distilled water (that's what the pump is for). You'll also need an air assist which is nothing more than a airbursh or large aquarium pump.

Something like this:

https://www.amazon.com/dp/B06XDKRYC6/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B06XDKRYC6&pd_rd_w=6o93T&pf_rd_p=10ebaf99-73de-4f5d-a994-e7f5fc52f86f&pd_rd_wg=o8iAi&pf_rd_r=WF7KZ4A648958FA1NRB9&pd_rd_r=0180bd8d-2a82-11e9-888f-47f1b1d850e8

That's it really apart from materials to laser.
Good luck and don't forget to hear over to the unofficial full spectrum laser forums for more specific help.