Hey Futo, you & me kid!
Make your own. You can season to taste & it's way cheaper.
Get a good roast, slice about 1/4" thick AGAINST THE GRAIN. Everybody say cut with the grain but then you have to strip it with your teeth. Against the grain & it breaks off easier for bite-sized hunks.
Trim off the fat - doesn't hurt to leave it on for short-term - I eat it up right away anyway.
Get a big bowl & throw in whatever kind of liquid spice stuff you like. Teriaki makes a good starting base. Dump in whatever the hell pleases you (mustard, salt, pepper, hot sauce, honey, Jamaican jerk is tasty, whatever, all kinds of stuff - play with it) & mix it all up.
Dump the liquid & meat in a gallon zip lock bag & mush it around. Close the bag after bleeding out the air. Throw in fridge. Mush it around every day for a week. Hang the pieces over the oven rack & S-L-O-W-L-Y cook at about 150F (you can set your oven on low & prop the door just open a crack). Don't cook it - dry it out ... may take a few hours.
If you have a SO in-house, you will be yelled at. It makes a pretty good mess (drips like hell) so line the oven bottom with tin foil. Better to do it in a backyard smoker if you got one - saves on the ears.
Keep eating to ensure proper texture while it's drying out. Start over 'cause it's all gone.