Doors and Windows - Tips on having a sliding door installed

I have a room that we would like a sliding door installed.I got a flyer yesterday on doors and widows installed pay nothing untill next year NOTHING.I do know that a 5 foot slider at home depot will cost me 600 Canadian.I have done some framing myself so far and has turned out good.Should i leave this job to a pro?.My int walls are wall board and plaster and the ext walls have siding.Also my home was build when a 2x4 was a 2x4.They are coming Tuesday night to give us an est on the door and installing it.What should i keep in mind and ask about please i do knot want to get burned.This is a well know firm.My deal is I plan on the door but low on funds at this time so this seamed like a good thought puting off the cost till next yaer.Any thoughts would be great.Thanks Don.

The slider at HD for $600 -- add another $200 for framing and trim mat'l if you decided to install it yourself -- you are looking at about $800. Stick $75 in the bank and in a year, you can do it, and it's paid for. On Tuesday you will get the price for having the slider installed and the payment delayed for a year. How much would you have to stick in the bank each month to cover that cost when it's due? Sure, they'll finance it for you, but at what interest rate??

I'll venture a "guess".....bet they want $2000 or more for the door......Get back to us on how close I come.

Thanks all,i will let the board know what the quote is.