$5k is common for consultants to demand for filing for an H1. Once you pay 5k, they connect you with their lawyer who will be handling your case (as well as other like you) who will ask for your docs, prepare your documentation/paper work etc. They time your application process such that it reaches on April 1st. After USCIS does the lottery it takes some time to get to know what happened. If you go thru, you will be assigned a "Case#" by the USCIS. If not, they will return your application along with the fees paid. Based on your agreement with your consultant, you will get back the money. Typically, consultants deduct the lawyer fees and give back the rest. Take care of the following -
1. Ensure the consultant has "good" reviews in redbus, h1bwiki, goolti etc
2. If possible find somebody who is working for them and call them and enquire. You can ask the employer for some references as well.
3. Check their "success rate" and "failure rates"
4. Ask them how they are planning to file your H1. Is it using a "Client Letter" or "as an employee of the company". If you have client letter, the chances of getting an "RFE" request for evidence is less, meaning success rate is high since the consultant can prove that they have a job for you and needs you. If they say they will file as an internal employee, then the company has to prove that they have sufficient work and business to hire you "within their company".
5. Ask them about what happens after you get your visa. There will be client interviews, for sure. But i am talking in terms of relocation - flight tickets, temp accommodation etc.
6. Be patient! The entire process takes atleast 6 months to complete. The earliest date when you can get your visa is october. Realistic time to go to US is Jan. Usually Nov/Dec is low time and less projects and hiring. If you think its too long a wait, ask for your employer/consultant for premium processing which gets the results faster.
Remember there 2 "most" important docs which USCIS will check for -
1. Client Letter or a project portfolio which proves the company has sufficient work for you.
2. Company Tax papers - this is very important if the company is a small entity. The companies usually provide this, but just in case.
Hope this helps.