Well boys and girls,
I don't know how many or if ANY of you have ever priced any Sunbrella lately but I have a commercial compound walking foot sewing machine and dabble in heavy duty sewing and have purchased smaller batches of yards of Sunbrella and that stuff IS NOT CHEAP! It ranges anywhere from around $18 a yard to as high as $80 per yard. And a "yard" is a 60" wide by 3' long. Sooooo, lets say your pontoon is oh, maybe a 23' version. The "average" pontoon needs around 25-30 yards of material for a cover. Now, using NASA Advanced Calculus water cooled computers, 30 (yards) x say, average of $45 per yard for the "good" level of Sunbrella, you're looking at around $1,350 for material.
Then there's the UV rated higher quality outdoor thread which while somewhat expensive, isn't too bad, maybe around $75 - $100 or so. Then there's the fastening system. A very large percentage of boat covers use snaps. Some, like ours, use a specialized clip that's sewn into the edges of the cover on each side that clip into the bottom open sections of the square aluminum tubing to keep the sides fastened to the boat. I'm not sure just what the cost of those plastic clips run each but just a guess might be around maybe say, $5 each or so. And I think our '14 25RCL Benny has around maybe 8 or so per side. So, that may add around $80-$100 (depending on length of the boat and if that's a reasonable estimate of those plastic clips) to the cost of the cover. Then use the snaps to secure the front and rear sections of the cover to the boat. And Stainless snaps are not cheap either. I have a couple hundred of those. l think our Benny has around maybe 20 snaps in the front and maybe about the same in the rear. So, add maybe around $20 to $30 in snaps.
All in all, you may have around (and again, this is just a guess) around $1,500 - $1,700 JUST IN MATERIAL. Then, THEN, there's the labor. Now, just because you already have a decaying cover, they (the top makers) most likely won't go with trying to measure an old cover. They'll want to take their own measurements because by doing that, they'll know just what's needed for making all their adjustments for seams, joints, pleats, darts, and hems and they add or compensate material for all that. There's the basic sewing of the material together to make a large sheet. Then there's the shaping of that large sheet to compensate for different dimensions and planes (vertical change vs horizontal change as the material transverses from across the top to down the sides, around the corners and then the front and back.
Soooo, when done and completely installed, your cover looks like it was made for that boat and not like a generic one with a bunch of sagging unused material or guitar string tight because of improper measurements. Todays labor, especially a highly skilled labor of quality sewing IS NOT CHEAP! I have no clue as to how many hours, start (of measuring) to finish, (walking away from a completely installed top) it might take as little as 20 hours or it might take as much as 40 hours, not a clue. And if the labor rate is say, oh, maybe say $50 per hour for an experienced commercial sewing person, you'd have maybe, just maybe around $1,000 to as much as $3,000 in labor, all depending on the labor rate and the total time involved. Soooo, with all that being said, you might have around $4,000 to $5,000 or so. Lots of guessing here.
Scott