.com - $7.34 + .18 icann = $7.52
.net - $4.65 + .18 icann = $4.83
.org - $7.21 + .18 icann = $7.39
.info - $5.75 new + .18 icann = $5.93
.info - $6.75 renewal + .18 icann = $6.93
1/15/2012 Price change
.com - $7.85 + .18 icann = $8.03
.net - $5.11 + .18 icann = $5.29
.org (sorry don't have this right at hand as I am traveling)
.info (sorry don't have this right at hand as I am traveling)
----FIXED BELOW---
Ongoing fixed costs, in addition to other obvious fixed costs (hosting, customer service etc.) and not including startup ICANN fees (as an aside the startup fees are pretty low now. Back when we started we had to post a $100,000 bond which essentially meant putting $100k in a bank which we couldn't touch).
Icann Quarterly Fee, with drop pool: 1114.254 = $4457.00/year
Icann Quarterly Fee, w/o drop pool: 371.414 = $1485.64/yr
(If you are grabbing names in the batch pool or essentially attempting multiple name registrations but with only a small percentage of resulting registrations relative to the overall registration rate.)
Annual Registrar Acc Fee: $4000.00 ($1000*4)
---Additional Variable Costs---
Additionally, keep in mind that domain orders are typically paid for by credit card. So in addition to the above the registrar is paying a few % points on their cost of the domain.
So for example if the base cost of a .com is (on 1/15/12) $8.03 with a 2.5% cc fee we are talking about another .20 or a total of 8.23 in cost.
Lastly, registrars have to keep money on deposit with the various registries to equal the amount of registrations that they will do in a month.
So if they are doing $10,000 of domain registrations in a month they would have to keep maybe an amount on deposit with (for just .com .net) Verisign of, say, $6000 to $15000 depending on the time of the month.
So there is the opportunity cost of that money.
That money that is tied up that you can't do anything with and that you are either forgoing opportunity cost of borrowing. If borrowing (assuming you can) I guess you could assign a cost of 3.5% to 5% for this on top of the domain cost as an additional variable cost.
That's off the top. I'm probably missing a thing or two and will update the above.