Lets start with your pricing being off. Reading helps:
The query prices listed above are prorated;
That is not 0.50 USD - it is 0.50 USD per 1 million queries and a low volume home system will not ahve more than a couple of thousand. SHould round to 0 or 1 cent.
Second, not every visit is a DNS hit - DNS uses extensive distributed caching, so it all depends. Things get complicated here - as caching is configurable (a) by you (per zone) and (b) depends where the hits come from (provider) as basically the DNS server the client uses is the caching point, not a hierarchy. Realistically I would expect maximum a coupel of thousand hits (max 10.000) for a typical home website.
That said - quite obviously - this is not something to discuss here as you lack - per the rules of this site - the authority to ask a question. Voting to close (not relevant question in professional admin capacity.
THAT AGAIN being said - use entrydns, that is free and more than enough for your needs. No sense in signing up for a service for 50 cents per month, especially when there is a free alterantive. I use entrydns for some time now and am very happy (entrydns.net).