$(`.buy${i}`).click(() => {
            $(`.pict${i}, .buy${i}`).hide(),
            $(`.otmena${i}, .bought${i}`).fadeIn(300);
        }),
        $(`.pict${i}`).dblclick(()=>{
            $(`.pict${i}, .buy${i}`).hide(),
            $(`.otmena${i}, .bought${i}`).fadeIn(300);
        })

const i = 1
const fnc = _ => {
	$(`.pict${i}, .buy${i}`).hide(),
	$(`.otmena${i}, .bought${i}`).fadeIn(300);
}
$(`.buy${i}`).click(fnc),
$(`.pict${i}`).dblclick(fnc)

const o = {
	buy: 'click',
	pict: 'dblclick'
}
// тут цикл по i
const fnc = _ => {
	$(`.pict${i}, .buy${i}`).hide(),
	$(`.otmena${i}, .bought${i}`).fadeIn(300);
}
for (cls in o) $('.' + cls + i).on(o[cls], fnc)

$(`.buy${i}`).click(fnc),
$(`.pict${i}`).dblclick(fnc)