My experience with PLA is it is pretty resistant to moisture absorption (although this might be because my room is very dry?). But target sells some vacuum seal bags that work well. You can also buy reusable desiccant packs on Amazon.
I use something similar to this in my safe. It seems to work fairly well and the gel balls change color when they absorb moisture so you know when to recharge it (just pop it in the oven for a few hours).
These are much cheaper and work great. https://www.amazon.com/Hydrosorbent-OSG-40-Dehumidifier-Desiccant-Chloride/dp/B0037Z8K3E/
You have to keep in mind that any silica desiccant will need to be periodically refreshed by heating it to remove the absorbed moisture.
I keep them in a tray in front of a fan for about 3 days. Probably overkill but rather fan too long than not enough.
Then i stick them in ziplock bags with one of these...
Hydrosorbent OSG-40 Silica Gel Dehumidifier Desiccant 40 Gram Orange NO Cobalt (II) Chloride https://www.amazon.com/dp/B0037Z8K3E/ref=cm_sw_r_awd_.7OYvbS0T549H
Hasn't failed me yet aside from the time i stupidly put one large fruit in the bag from a separate batch that wasnt dry enough. Whole bag got soggy and gross smelling after a week. Lesson learned
I use something similar to this. It changes colors when it is saturated. Three hours in the oven and it is good as new. https://www.amazon.com/dp/B0037Z8K3E/ref=cm_sw_r_cp_apa_glt_fabc_GDCA9SD309MXPZJ3BY3A
These are the ones I use. I keep my spools in 5 gallon buckets and toss one of these in.