So roughly $1300 in bandwidth, possibly could cut some there by putting Cloudflare in front of static assets, but no idea how much of that is from static vs dynamic assets.

Most of the compute cost ($2400) goes to an m4.xlarge and an m5.2xlarge. That could be reduced by using reserved instances - but there's other gotchas there if you're likely to change that anytime soon. Google cloud is much nicer in this regard with the auto discounts for continuous usage.

The provisioned IO for EBS $2500 makes me sick, but may be necessary to get adequate performance.

Honestly you could move everything onto two dedicated servers (one as a hot backup) and cut this down to $1000/month and get better performance. But that's the AWS tax.

I use AWS all the time for work, but I would never build my own business on it.

I agree with most of this. Some ways to save money are

1) Switch to the newest instance families

2) Save up the cash then reserve your instances.

3) Don't bother with the provisioned iops volume type, just use GP2 volumes large enough to give you the baseline IOPS you need

4) In general you have more block storage and snapshots than I'd expect, maybe that can be cut back?

the benefit is outsourcing operations. If he used dedicated instances he'd need to manage his SQL server, disks, deal with hardware failures...etc.

7k$/month is cheaper than hiring an additional head.

I don't think of RDS as zero-maintenance, but I'll agree it's probably less. You get different and arguably more complex problems under load with things like EBS performance. I'd rather have local disks which are simple for me to understand and debug.

Basically, with his skillset, maybe it makes sense. With my skillset I'd rather have the hassles with the dedicated setup.

I'm not sure I agree, now I have no clue where he's from, but assuming he would save 7k a month that'd be 84k a year.

Obviously there's other overhead/costs involved, but surely he could find somebody for 60k+ a year (I make less then that at my current development job but I'm from Michigan)?

That single person you are paying a sub-par wage won't be providing 24/7/365 support, which is a big benefit of AWS / cloud providers. It's also a bit of insurance on your hardware in case of failures, free replacement. Finally, if something catastrophic was to happen, with a recent-ish offsite backup it's usually pretty trivial to setup on a different region or even cloud provider. With your own hardware, that's a bit harder.

I agree though with one of the parents, AWS costs here can likely be significantly reduced. I cut costs in half by (a) reserving instances and (b) thinking about EBS and downgrading / downsizing where possible rather than using the defaults.

Could save (edit: not $3600) $1873 per month by using Linux instead of Windows. I see you are using SQL server, probably C# for the code, might be worth looking into running it with Mono.

That's more than he spends on EC2 servers entirely. So your math is off by at least an order of magnitude.

To the downvoter, your math sucks too!