I can't speak for the success but I have experience with them.
typically the process is that you take medication starting CD3. Some people take Clomid, typically they start you there. Clomid is cheaper and it is a pill. You end up with less follicles on Clomid. If that doesn't work you can move to something like Gonal F and it starts on CD3 also. This medication is very sensitive and you have to be careful with your dose. Gonal F is also injected by needle nightly. You can easily end up with way too many follicles and your IUI will be cancelled. Clomid is not very expensive, I forget how much it was. Now Gonal F on the other hand is based on your dose. Typically you start at 150 per day so that is about $150 per day. Just hope your dose is lower.
You take each medication daily and at my clinic I get daily blood tests and ultrasounds to monitor follicles and Ovulation. Once they determine that your follicles are a good size (possibly around CD10) then you get a "trigger" in order to cause ovulation, mine was called Ovadril. You take that needle at 10pm and you go in for your ultrasound 36 hours later.
We dropped DH sample at the clinic in the morning to be washed and a couple hours later I went in for the IUI. You go up on the table and they use a speculum like you are getting a PAP test. From there I didn't really see what they used but they inject the sperm up into your cervix. It just takes a few minutes and you really don't feel a thing.
Take a look at this video:
https://www.youtube.com/watch?v=qCdIiLLF0vw
I had 1 IUI and AF came at 9 dpo. I typically go to 14 dpo so that was a shock. This month I started taking progesterone at 1dpiui. I get the progesterone in suppositories and it cost $100 for 14 days.
Word of caution....watch it with the medication that is injected like Gonal F. I ended up with like 17 follicles so they cancelled the IUI. That was quite upsetting when we put all that money out for the medication. The next month they dropped my dose dramatically and I ended up with 1 follicle. That was another wasted month because we were not going to par $350 for an IUI on one follicle. This month we had 4 follicles so I am hoping for the best.