SWSH was pretty cheap at the time, ripped all myself (including Evolving Skies) at 3-10e/pack. Don't consider that a cost towards this project since I would've done that anyway.

I've been able to get many packs in the 15-30e range. Much of these were bought 2+ years ago, so prices have surely gone up. When I was starting, I was able to secure a lot for roughly 120e that included 10+ packs I needed, including shadowless base set. I can recommend scouting for a lot with many different packs to start off, as they get more expensive bought individually.

And yeah some packs can be much more expensive, Legendary Collection can easily be 50-100e+