We considered as well having a lawyer and all three where we were at asked for 5-7000$ in advance for their services. I had a hard time understanding why they charge so much, as we had a very simple case with no complications, no previous marriages, no criminal records, nothing. Therefore we decided to do it ourselves. Believe me, unless you have a very complicated case where you would need legal advice, you can fill up the forms by yourself and have a successful application without anyone`s help. Just make sure to read the guideline from A to Z, ask people here on this forum if you are unsure of certain things and it will be all fine. Our case was approved in 10 months for both 1st and 2nd stage together and I landed in 11 months.
Good luck!!!