The extract is from the "Notes from a Dead House." Sushiloff was a prisoner who had been sent to Siberia merely for colonization, for some trifling breach of the laws.

During a fit of intoxication he had been persuaded by a prisoner named Mikhailoff to exchange names and punishments, in consideration of a new red shirt and one ruble in cash.

Such exchanges were by no means rare, but the prisoner to whose disadvantage the bargain redounded, generally demanded scores of rubles; hence, every one ridiculed Sushiloff for the cheap rate at which he had sold his light sentence.

Had he been able to return the ruble (which he had immediately spent for liquor), he might have bought back his name, but the prisoners' artel, or guild, always insisted upon the strict fulfilment of such bargains in default of the money being refunded; and if the authorities suspected such exchanges, they did not pry into them, it being immaterial to the officials (in Siberia at least) what man served out the sentence, so long as they could make their accounts tally.

Thus much in explanation abbreviated from Dostoevsky's statement.
"Sushiloff and I lived a long time together, several years in all.