Can anyone recommend a pedal to get a decent slapback using tube amp and 3 string cigar box guitar? I'm thinking Scotty Moore, Stray Cats through to The Cramps.
Loads of demos on YouTube of people using various delay pedals, but also using high end 6 strings with expensive amps.
What kind of budget do you have in mind? Analog (or analog-ish) delay pedals start out at about $25 and go up to $1000 or more for boutique ones with unobtainium chips or actual tape.
I've bought several inexpensive (less than $50) ones and the one I'd recommend for slapback is the Behringer VD400. The Ammoon/Rowin/Donner nano pedals aren't bad, they're a repackaged Hotone delay. However, it has a design problem with the power plug and the slapback is a little too bright for my taste. The Behringer Vintage Time Machine is a decent copy of the EHX Memory Man but, like its parent design, you have to like how it colors your tone.
Going up in price, the MXR Carbon Copy, Dunlop Echoplex and Boss Waza DM2 work well. I've also been looking into the Digitech Obscura.