4GB RAM Droplet

Let's take the popular droplet plan offered by Digital ocean and compare it with the equivalent EC2 instance.

Month Cost Hourly 0.03 x 720 = $21.6. So they offer $20/month if you are ready to pay upfront. That makes it yearly.

$20 x 12 = $240

4GB T2 Medium EC2

With the on-demand instance, you can stop or terminate the instance and Amazon will discontinue charging you the hourly fees.

With the No-Upfront Reserved Instance, you commit to paying the hourly instance charge for every hour of the month for 12 months, whether or not you are actually running a matching instance.

Because you promise to pay for the whole year, Amazon gives you a discount on the fees for that year.

So immediately convert your on-demand EC2 instances to no-upfront if you run it full time.

Comparison with Reserved Instances

Let's see how the EC2 prices compare against droplet of the same capacity.

Reserved instance	Yearly cost	Droplet Diff
No upfront	0 + 20.95 x 12 = $251.4	+ $11.4/yr
Partial upfront	120 + 10 x 12 = $240	+ $0/yr
Full upfront	235 + 0 x 12 = $235	- $5/yr

If you take the monthly plan of droplet 4GB server, you get an advantage of $20.95 - $20 = $0.95/month. $11.4/year isnt much considering the services AWS offers. Besides, if you consider the long-running, dependable server for a year, which you prefer to pay for the full year, AWS seems to be a better option with a cost advantage of $5/yr.

Conclusion

An advantage of saving $11.4 over a year doesn't seem worthwhile to move to Digital Ocean with your EC2 instances.