Yikes! Just got an estimate to refinish my porch

[dennis thompson]

Just got an estimate to sand and stain my porch floor. It’s 9’ x 30’ plus five stairs each 7’ x 1’ and currently has a Benjamin Moore stain on it.
The estimate is $3092 which seems like a lot to me.
I’m thinking about doing it myself. I can rent a sander for about $70/day
So just let me guess at costs:
Sander for two days $140
Sandpaper $100
Stain $200
Who knows what else $150
Total $590
So do you think this is a do it yourself project?
What do you think of my cost estimates/guesses.
What stain would you recommend?

Thanks