Helmet $50
Vest $50
Prop pistol $35ish
Rifle $30-50
Goggles $20
Boots $whatever is comfortable and looks plausible, I’m not going canon with these, but the boots I will use were close to $200
Pants and shirt $50-100
Holster $55
Now, that doesn’t include a few other pieces that you can add to put it over the top…
Also, please, if you do get the helmet, make sure you remove the “GIRO” from the front and the “Bad Lieutenant” from the back. Goof Off works great on the GIRO, the Bad Lieutenant took a bit more scrubbing.
Second also, there are MANY variants that people are coming up with that are sorta spun off the basic marine. Force recon, SAR, the Razor boarding team are just a few examples. You might be able to find a cheaper (and cooler for Atlanta in August) costume from those. I’m also sorta doing a Razor semi off-duty marine getup as well, you know, for partying hearty at night.
If you are on a really limited budget, you could always do a cardboard cylon.