Sometimes the easiest thing is to simply put 'yourname.com'
But what does that tell the search engines? Are people going to type in your name or catch phrase looking for your services if they haven't heard of you yet? Probably not.
A good idea is to have more than one domain name with a 'redirect' pointing at your main website. You can many domain names pointing at the same website.
(I can help you with this easily)
What if you have a domain name but you're not ready for a website?
Have you typed in your domain name and seen a page full of ads for godaddy.com or some other domain service? Or maybe a notice that 'this website is under construction?' Ouch. That never looks good.
(Those godaddy.com ads are the worst! They look like an ad for a bar or a nightclub)
Then you need a "Landing Page" A temporary one page simple website with your information on it including contact info. An excellent solution while your budget waits for a website.
I am helping a lot of people with their landing pages these days and would be glad to help you too. I can always be found at www.webtimegraphics.com if you need help.
In the meantime, good luck and Let's Get Some Website Traffic !