How I saved around 7-8% for my lootboxes.

Use the cashback and giftcard sites linked below. Disable your adblock/clean cookies to make sure your purchases track.

Links for sign up:
Cashback site ExtraBux
KarmaKoin gift card site CardCash

1. Login to the ExtraBux site and search for CardCash, click through that. They'll give you 1.5-2% back. You can redeem to your PayPal afterwards.
2. Search for KarmaKoin in CardCash gift card site, they're selling it for 4% off. Delivery is instant to your email. Pay with a reward credit card for 1-2% more cashback.
3. Use the KarmaKoin code you got via email to pay on WG's premium shop. You'll have to click 'Show More Methods' for KarmaKoin to show up. It's the one with black icon under CVS for me. Pic: https://imgur.com/BlKf4ng

I got the 75 boxes package for $92ish after $2 from ExtraBux, $4 discount from CardCash and $2 in credit card rewards. Only got the Bisonte and ISU though, so probably an alright deal..

Notes:

1. First of all I wish WG didn't make new content lootbox exclusive, but we're stuck with what we get. Please don't gamble unless you can afford it. I bought 100 boxes last year and didn't get a single premium tier 8, so RIP.
2. The KarmaKoin thingy works for most WG purchases, not only lootboxes. Check the premium shop if it's a payment method for you before buying.
3. All the links and sites are for NA, Idk if it'll work in EU/SA. Maybe some EU/SA plebs unicumswill confirm in the comments…