There is not much of a price difference (at least where i live) between lowes vs home depot 3/4" mdf. I'm talking a difference in cents.
Both stores sell for around $30.
The best place to find it cheaper is to call all your local lumber stores, they always have it cheaper. You have to ask if they sell to customers and if they sell per sheet.
They will not allow you to use their panel saw for obvious liability reasons but WILL allow the pimple faced 19 year old with the fancy apron make your cuts for you. If your vehicle is too small to carry a full sheet have them cut your boards like 1" too big. You can trim them to actual size at home.
I've been using power tools for 20+ years. Nothing is more embarrassing than having that kid with the nasal voice tell me "Excuse me sir, you're not qualified to operate that saw. Please step aside."
Then you watch him struggle with the setting and even the cut. When you get it home you realize the damn thing isn't square anyways. Happens when a $1500 panel saw get rammed daily by forklifts driven by just as incompetent weenies.
Yes, there have been times when I have gone and the cuts have been quite a bit off but thats why its important to know who you want to make your cuts.
It's important to know WHO is making your cuts, there are many people who work in lumber at both lowes and home depot that take pride in their wood craftman ship and the last time I'v gone to get sheets, we usually have them cut off a 13" strip long ways so that the sheet will fit in my car. The last couple times we have had them cut multiple pieces, the cuts have come out almost exact with a +/- 1/16". So IMO is really depends on who you get to cut your wood.
Well $7/hr only gets so much. It also depends on location. When you deal with Lowes or Home Depot they truly employ idiots, for the most part. Nobody can argue that. I asked one kid if the deck screws I purchased were appropriate for the type of pressure treated lumber I wanted them to secure I got a blank stare.
This is why they sub contract their work out to local builders. The training/experience isn't their problem anymore. As long as they're licensed.........