A Waterpik 3100 water flosser sells for about $24.99 on eBay, from 73 sales between Jun 27, 2026 and Oct 7, 2026. Most sell for $20 to $29.75. Used ones bring $22, new ones $28.36. At local online auctions it has gone for $4.60.
$24.99eBay sold, middle price
$20 to $29.75typical range (middle half)
$22used, 33 sales
$28.36new, 40 sales
$4.60local auctions, 4 closed
55sold in the last 90 days
What it goes for, whereLocal auction, eBay new and used, and what you keep after every fee.
Every eBay sale over time73 sales, Jun 27, 2026 to Oct 7, 2026. Tap a dot for its price.See the numbers
Month
Sales
Middle price
Jun 2026
1
$24.99
Jul 2026
16
$26.50
Aug 2026
18
$26.48
Sep 2026
24
$24.49
Oct 2026
14
$22.97
Where the prices fallThe shaded band is the middle half of sales: $20 to $29.75.
The flip math
What one Waterpik 3100 is worth to a reseller, line by line.
Sell one on eBay
Sale price (low end of typical sales)$20
eBay fees (13.6% + $0.40)−$3.12
Shipping it to the buyer−$10
Returns and duds buffer (15%)−$1.03
You keep$5.85
Buy one at a local auction for the typical $4.60
Winning bid$4.60
Buyer's premium (18%)+$0.83
Sales tax (9%)+$0.49
Lot fee+$2
You pay$7.92
Cash in hand (keep − pay)−$2.07
To keep at least 2 times what you pay, bid no more than $0.72. Above $2.99 you lose money after every fee. Run your own numbers.
Local auction prices
4 single Waterpik 3100 lots closed at Kansas and Missouri online auctions we track, at a middle winning bid of $4.60.
Closed
Winning bid
Nov 2, 2026
$3
Oct 24, 2026
$3.20
Oct 16, 2026
$6
Oct 11, 2026
$10
Selling notes
66% of sales shipped free; the rest charged a middle $7.09 for shipping.
15% sold through Best Offer, where the real price can be lower than shown.
The last 60 days are steady against the 4 months before.
6 sold in the last 30 days, 55 in the last 90.
Questions
How much is a used Waterpik 3100 water flosser worth?
About $22 on eBay, the middle of 33 used sales between Jun 27, 2026 and Oct 7, 2026. Most used ones sell for $20 to $29.75 once new ones are counted too.
What does a new Waterpik 3100 water flosser sell for?
New ones sold for a middle price of $28.36 across 40 eBay sales.
How fast does a Waterpik 3100 sell?
6 sold on eBay in the last 30 days and 55 in the last 90. Prices are steady against the months before. 66% of sales came with free shipping.
What does a Waterpik 3100 go for at auction?
At the Kansas and Missouri online auctions we track, 4 single Waterpik 3100 lots closed at a middle winning bid of $4.60, against $24.99 on eBay.
Is a Waterpik 3100 worth flipping?
Sold at $20 on eBay you keep about $5.85 after fees, shipping and a returns buffer. To double your money, pay no more than $0.72 as a winning bid with an 18% premium and 9% tax.
73 eBay sales of the Waterpik 3100 from Jun 27, 2026 to Oct 7, 2026, each one checked to be this model (at least half name it in the listing; the rest match it closely).
eBay prices are completed sales (what buyers paid), not asking prices, from our sold-data provider. We keep only sales of the same product: parts, accessories, bundles and look-alikes are dropped before anything is counted.
Local auction prices are winning bids on single-item lots at the Kansas and Missouri online auctions we track (HiBid and Equip-Bid sellers), read by our own lot reader. Lots of several units are left out.
The money math uses our standard costs: 18% buyer's premium, 9% sales tax, a $2.00 lot fee, eBay's 13.6% + $0.40 fee, shipping at cost (never counted as profit) and a 15% buffer for returns and duds. Members set their own.