hi there, my experiences are:
i once payed a submitwebsite, I never came in top, only some searchengines like aol and hotbot, my page stood by the top 10.
But at google it is a search of 40 pages, I don’t know why and how it comes that google is different.
But why pay, i believe there is a program submitwolf, you should try it, if you are convinced you even can buy it, and have more searchengines available to submit.
I believed there is a demoversion, with only google and some other well known search engines.