Sure you Can do it yourself, but be ready to work on it carefuly and grab as much proof as you can to support your story.
I didn't have any lawyer but Iike Kadija said legal aid can pay immigration lawyer if you find one that took lagal aid (most of them don't want to) and you must be eligible and have low income.
Hardest part in my opinion and in my case was writing my story where I include my H&C ground and got all the proof I need to make sure Imm officer will understand my situation clearly. That part took me so much time because I wanted it to be perfect and I don't regret. The Immigration forms part was easy for me because I was used to them.
And yous can alway call your MP office to see if somebody can check your application before you submit it ( I don't know if every MP office does this)
Here two link that helps me a lot for my DIY H&C application.
http://www.solidarityacrossborders.org/wp-content/uploads/HC-kit-EN-FINAL.pdf
http://overseastudent.ca/migratetocanada/IMMGuide/CICManual/ip/ip05-eng.pdf#page88