There are still deals to be found. I see them on Facebook and Instagram sometimes, and I know plenty of people that are still doing well. It's all relative though.
If you want to find the deals though you have to put in the time, that's the best advice I can give.
For thrifts: find a good route and hit it as often as you can, vary the times, and log which is working better for you in terms of getting good stuff that's out on the floor. See if you can determine any patterns (there may be none) and work from there.
Craigslist and Facebook Marketplace have the occasional gems but you need to be fast. Determine if you'd rather spend your time hunting, or spend more and have the free time. As I get older I'm willing to pay to just have it so I don't have to scrape through crowds but I still hit my routes occasionally. Normally it's no good but sometimes I do well.
If you're at all interested in modern stuff check out the Gamestop threads, there are people that have flipping there down to an art. Gamestop has helped my a ton with my Wii U collection and has also helped my keep my overall prices super low. When you cut out shipping it adds up, even if you're still paying tax.

