Arleth y Josean

Have you reviewed the guide/ process at all at least to have some familiarity of the process?
Income is as in your personal income, that gets taxed by the government you need to be over a limit determined by the govt. This would have nothing to do w/ RapidVisa or any other service. I imagine a service like RapidVisa should clearly outline the fees/costs themselves.
If your OP is based purely on fees, I have no idea how much RV costs and what they may include or not in their services. Theres incidentals like printing/shipping/tracking but thats really not that much relative to everything. Fees for filing and the medical ~$6-700

I don't believe you'll find an aproximate. You can get a guess but every case is different and not all cases are done in the same time frame.

My case will take 148 days from the time we filed to complete (not including waiting for the visa itself). It took 36 days to get my 129f petition approved.

BUT.. again, doesn't mean you'll be that case. There was a person here who filed in April like I did, and they didn't get their 129F petition approved until late august. No RFE.

Remember though, if it doesn't happen as fast as you expect it, it doesn't mean it's not within what USCIS considers okay. While most people seem to be completing their K1 visa within 6-7 months, USCIS allows 5 months JUST for the 129f Petition before they start taking "WHY IS THIS TAKING SO LONG" calls, according to their current processing times.

http://www.visajourney.com/timeline/
http://www.visajourney.com/content/guides
Have a look at recent timelines for the K1. And here is the guides for k1 including step by step, flowchart, etc.

Not met in the way you're thinking. You have to had been physically together at some point in the last two years.... you're ok as long as you've been together in person.

No one can guarantee an outcome/result. All the visa service can do is to fill out forms with information that you supply. If you want to do it yourselves then simply do some research here on VJ. You will find that most have done all the work without using a service or an attorney.
If you feel that you will not be able to complete the forms accurately then maybe you need a service to help you avoid the simple mistakes. If you have a very complicated situation then maybe advice from an experienced immigration attorney will help.
The guides, sample forms, and forums here in VJ have a lot of great information. Do some reading and then decide for yourselves.

Para la Visa K1 no se necesita ni abogado ni usar una pagina como esa. Si conosco de alguien que la uso y le fue bien pero es gastar el dinero sin necesidad. Este sitio de visa journey te da toda la informacion necesaria para hacer la solicitud de K1 y lo mas importante es organize los documentos necesarios y la evidencia. Si usteded se conocen y tienen evidencia no nada dificil que llenen la K1 siguiendo los paso y guias de esta pagina.

Rapidvisa is a reliable company.They are always available for any questions and concerns you have, its worth the small price for peace of mind. They cant speed up the processing but they can avoid delays due to errors or omissions in your petition.Good luck in your journey