I know of a couple where the guy earned 130 pounds a week part time, and lived with his parents too. The wrote a statement to the ECO saying with their blessing they would provide housing and food towards the support of the wife. The got their visa. I thnk the ECO looks at what money the breadwinner is earning and also what his monthly costs are. If you partner can show he earns more than he spends he will pass your application.
The ECO will want to see a bank account that Has money in it. NOT an overdraft - as we found out to our cost on our first application. The ECO will be even more impressed if you can both demonstrate that you already have the money saved to buy your plane ticket to get to the UK, and also suffiecient money to have the wedding that you are planning.
Hope that helps.
