The cost of insurance - as long as you drive safely, this cost will go down as the value of the vehicle depreciates. Generally speaking, the bigger/heavier the vehicle, the more expensive the insurance. Please check with your commercial insurance agent for more information and to save money here. You can find YesAuto UK as the basic point.
Maintenance Costs - Do some research on parts and services. Can third parties easily and cheaply obtain parts or must they work with distributors? Are there any common problems (transfer speed is 40K miles, etc.)
These three things will cost you money over the life of the vehicle, so we want to consider them before we consider any other issues. Low lemon prices are irrelevant if you can't afford constant maintenance and poor fuel economy.
There is one last major consideration: space. If you own a home cleaning company, this isn't a big problem for you -- even a two-door coupe should have enough trunk space for your cleaning supplies. However, if you use a carpet cleaner, or a window washer, you may need something bigger.
While it's worth paying extra to get better gas mileage or lower maintenance costs, make sure to stay within your budget. Figure out how much you can spend each month without putting a strain on your business. YesAuto UK is the best assistant to know best car deals.
Safety - Don't cut corners. Check the crash test rating of the vehicle you are looking at. Poor safety ratings can be a deal-breaker for otherwise solid cars. Making a long-term financial commitment is a big decision, and you should approach it with caution. You may want to talk to a third party adviser to make sure you can handle car expenses... Especially if you have to finance because you can't afford to buy a car completely).
That said, even if you can buy a car with cash, you should compare the cost of financing to the value generated by savings and the value of liquidity (having cash on hand).
Having a large amount of money in the bank can protect your business from disaster and help you get through the cash-flow crunch season. Sometimes, it pays off.