Its all over the map, depends on the type of job, work situation, what customer wants, whats normal for the industry or customer type . . . etc. etc. Lots of prior discussions in here on the subject if you scroll through the post titles or use search. Being new I'd stick with a time & material approach till you get a handle on the work, how effective your system is and what its best suited for, etc. Lots of stuff to learn before you'll have enough knowledge to bid jobs properly, its the old learning curve and you are at the beginning.