Gun Broker is a place to buy them, Joe Salter has some as well.
You can Watch the EE here for them.
Do you want Solid Frame Double Action, Or single action Spur trigger?.
Colt New lines are the nicest spur triggers In my opinion.
Forehand and Wadsworths are the nicest Solid Frame Double actions In my opinion.
Harrington and Richardson and Hopkin and Allen DA's are decent, I'v had acouple that were fairly accurate for pocket guns.
I'v owned two Iver Johnson bulldogs, didnt care for them much, but maybe just me.
300-500 can get you a good solid spur trigger, many companies to choose from. around 800 and up for a good Colt new line.
400 and up for a decent to nice solid frame double action .32 rimfire.
Hope this information helps.