In Shakespeare's The Merchant of Venice, for how long does Bassanio need the money?
Bassanio needs the money he borrows from Antonio for one specific purpose only. He confides to Antonio:
In Belmont is a lady richly left;
And she is fair, and, fairer than that word,
Of wondrous virtues: sometimes from her eyes
I did receive fair speechless messages:
Her name is Portia ...
Bassanio has received what he believes is an indication of Portia's interest in him through her look, which sent him positive messages. He then extols the myriad virtues of the many suitors who have come from far and wide to woo the beautiful and wealthy Portia. He is distraught, for he wishes to do the same, but lacks the means to prosper in this grand venture. As he passionately exclaims:
O my Antonio, had I but the means
To hold a rival place with one of them,
I have a mind presages me such thrift,
That I should questionless be fortunate!
He believes that should he have the capital to compete against his obviously wealthy competitors, he would unquestionably stand a good chance of winning Portia's hand. Bassanio clearly needs the money immediately and for such period of time as when he has completed his quest. This period is not specifically indicated. One can assume that he needs time for preparation and the journey to Belmont, all which might take a number of days. However, he has to rush since he does not wish to give any of his competition the opportunity to be successful in their venture.
The generous Antonio offers to help, but states that he has no capital at hand. He does, however, ask Bassanio to travel to Venice where he could obtain a loan by using his good name as security. He, Antonio, would for his part, also strive to raise the money his good friend needs.
We later discover that Bassanio needs three thousand ducats which he borrows from Shylock, the Jewish moneylender. Antonio then signs a bond guaranteeing to repay the loan within three months and would, if he should default, allow Shylock to cut out a pound of his flesh. Although Bassanio beseeches him not to sign the deed, he ignores his appeal.