Hi!
If you ovulate on your own without clomid, I would not recommend taking it. You may want to consider watching the ovulation cysts developing on your ovaries during the AI cycle to be sure that it is a good cycle. If you don't develop a nice follicle ( 20mm or so) or two, you may then want to consider something to help such as Femara. I like it better than clomid because it interferes less with the uterine lining and cervical mucous, also, lower risk of multiples.
I think maybe the biggest advantage of the HCG injection is timing. You want to maximize the potential that the egg is mature and released at the same time as the sperm are inseminated. If your body is predictable and your schedule is flexible and you don't have to drive long distances, etc, I would suggest trying without the "trigger shot", but if you can't be seen everyday for an ultrasound, for whatever reason ( including $) it might be worth your while to consider.
One other thing that has been shown to increase conception rates is accupuncture. There are actually some well done scientific studies showing a benefit. If you have access to a good practitioner, throw that in there too!
Hope this is helpful!
Good Luck!
Dr B