I know that at prices this low a huge markup may still not be a huge price to pay to save time, but the markup really is pretty big.<p><pre><code> 1 day = 940% markup ($4.52 more)
1 week = 197% markup ($6.64 more)
1 month = 73% ($10.60 more)
</code></pre>
But... as said, while the % looks big, if it saved me hassle then who cares about a few bucks. I guess my issue is that the page doesn't sell me on that being the case, so it seems like just getting EC2 service (possibly with less access) and for a higher price.
You could try also marketing it to Freelancers who need to develop an EC2 app for a client. This way the client can easily provide the freelancer with a development box for a week or a month.