Being patient and knowing exactly what you want helps. I have bought 3 bikes over the last 2 years. 1 from craigslist and the other 2 from ebay.

The first was a Ridley Helium in mint condition from Craigslist. It was a 2013 model that I bought in 2017 was full Ultegra and came with brand new HED Ardennes wheelset. The previous owner was a runner and bought the bike to nurse a knee injury and rode it for about 600-800 miles over a summer and after the knee got better he didn't feel the need for it anymore. He had all the paperwork and documents from the purchases along with all the pieces and parts that came with the bike, also gave me the pedals and shoes (They were my size) as he wouldn't need them anymore. It took me about 3 months of searching to find it. All the paperwork added up showed that he spent about 4800 on the bike, pedals, shoes and wheels. He sold it for 1400. (I couldn't in good conscious bring myself to negotiate the price although he probably would have)

The 2nd bike was an ebay purchase from Bicyclebluebook. I got a 2016 Diamondback Airen 5C with full Ultegra for my wifey for 1200. It was in mint condition, still had stickers, no scratches, free shipping, no tax. I was amazed at how nice the bike was packaged and shipped. This bike brand new listed for close to 2800.00 and at the time we purchased I could find it listed for 2000 - 2200 as last years model. It was hard to find the right frame size but BBB had the exact framesize we needed and had it listed for 1300+ I put in an offer for 1200 and they took it.

The 3rd bike I bought was from Random Bike Parts. I got a 2017 Blue Pro-Secco from them for 1100.00. Full Ultegra and it seemed like it was a lot buy from RBP and they were just dumping them. The bike was in great shape. I had an issue with one of the tires (It had a tear in the tire) and they gave me a 25$ refund.

If you have no problems doing a little of the basic work yourself buying online can be a great deal. Even if you have a good LBS that is willing to put it together for you.

Currently Random Bike Parts still has a few of the BLUE road and gravel bikes leftover from last year. Ultegra and 105 bikes are listed for 1300.00 but they have a special right now if you use the code BLUE20 you can get 20% off the list price. So you can get a great deal for about 1000.00 on a full carbon ultegra gravel bike or 105 road bike.

-Sean