AWS loves startups that could end up being huge customers so they're willing to slash bills upfront to help you get to growth stage; not only will they assign you an account rep but they'll have a rep whose job it is to build a good relationship with your VC. Speak to your account rep. Have your VC speak to their Amazon rep. Push them to cut your prices.
I've known startups which have cut their monthly bill by six figures going this route. AWS doesn't want your startup to fail and on the margin these resources cost them close to zero so they're willing to deal, make use of it.