Maybe this has been talked about before but I failed to find anything.
Does anybody have a good source for wood that is priced right.
The GF wood is nice stuff and I use it, but most of the time any wood will do for most
of my projects.
Amazon has a good selection but everything I have seen is only
2.7mm thick and the GF proofgrade draftboard is 3.2mm thick.
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Also keep in mind that wood swells and shrinks dependent on humidity/moisture etc. so a difference of .5mm might well be the difference in season or location
Even acrylic (which doesn’t change that way) has an “acceptable” amount of variation in thickness
If you’re going to use non-PG materials, why does a slight variation in thickness matter?
In my experience “Revolution” plywood is the least expensive out there and can be found at Lowes or similar. but for actual wood you might have a local specialist that will not charge shipping, or an E-bay seller with a smaller selection but reliable folks with a good selection there are a number…
Thin Scroll saw wood pricing sheet,
Green Valley Wood Products
Baltic Birch Plywood - Woodworkers Source
Are the bigger ones
Mostly projects that have interlocking parts where designed for the thicker wood.
But most of the time makes no difference
Hardwoods, and plywoods, won’t come finished and most won’t come pre-masked. Unless you’re making purely 2D things, however, the pre-finishing is usually a bad thing and masking is no big deal. For that reason I pretty much only use non-proofgrade hardwood.
I don’t have a preferred supplier yet, but be careful in saving money. You may find stuff advertised as “sanded to 120 grit” to still have a bunch of saw marks or other deformities. I’ve been able to work around any bad pieces, but you certainly don’t save time. And I’d be surprised to find consistent thickness. Be prepared to adjust designs for thickness, cut large and sand flush like evansd2 does with his finger joints.
Exactly what @caribis2 just said, I’ll just point you to this post I made about this challenge when designing interlocking parts:
I have found that unless the wood is ultra hard a rough sand is little issue especially if I am doing a deep engrave where that surface goes away anyway, Even otherwise a 400 grit belt sander makes short work of any of it.
here are some of my wood sources:
www.inventables.com/categories/materials
www.trotec-materials.com
www.richardscraftwood.com
www.macbeath.com/
cherrytreetoys.com
www.realwoodpaper.com
https://www.glveneer.com
https://www.certainlywood.com
https://www.boulterplywood.com
https://www.oakwoodveneer.com/
https://www.dyed-veneer.com
http://www.thewoodgallery.com/
ocoochhardwoods.com
www.dndhardwoodsonline.com
https://www.richardscraftwood.com/
www.cardsofwood.com
http://www.infinitywoods.com
https://www.kencraftcompany.com/
Over the years, I have used them all. various strengths and weaknesses.
Thanks everyone, getting some good ideas and some good sources for material.
So far I am just making anything and everything and learning how to use the GF and Inkscape. 
We have a store here called Macbeath Hardwood - I buy sheets of maple ply for a very reasonable price and cut them down myself. Perhaps you have something similar close to you?
This past holiday season I purchased and cut several hundred 1/8" boards from Lasered By The Creek. Not a single glue pocket or void. Cuts very nice and clean. Also has a proprietary wood core instead of MDF which allowed me to cut faster (ie. speed 195) and since it cut cleaner I had less maintenance cleanings between cuts.
Personally I’m mostly in 2D things and finding out cheaper pre-masked options would be valuable to me. Especially if available in Europe as well…
Late to the party but appreciate all the info in this thread. I am ordering the sample pack from Ocooch Hardwoods (your first link). I am looking for laser material for an outdoor wood sign that will be cut/engraved, stained, sealed, and relatively protected from the elements in northern NY and considering tigerwood, white oak, or quarter sawn white oak (likely leaning towards that one), based on their helpful website descriptions. Very good information on this site and I learned a lot, thank you!
You will probably like these threads:
Check out #1a for even more info on material sources and #6 for information in settings.
Ocooch is great for semi-exotic hardwoods, but unless they have changed, much of their Plywood has an MDF center, which is not good, especially for outdoor work.
They do carry Baltic Birch, which has legal requirements that make it good stuff, unlike plain birch, which can be quite variable.
Smokey hill has some pretty damn good stuff
Their Baltic Birch is marine grade (water resistant) and sanded butter smooth, it’s nice.
These are other sources for plywood in 12x19" or 12x24" size, with two good faces and a finish on both suides, and a core suitable for laser cutting with a Glowforge Performance Series laser, comparable to Medium/Thick Proofgrade plywoods:
Maple
Walnut
Cherry
Basswood
For the Aura/Spark owners:
12x12", 1/8" thick, MDF-free lightweight plywood for diode lasers, similar to the “light” Proofgrade plywoods:
Nice list. Added to #1a.