One thing that we are often asked when we tell people about our trip is how much this kind of life costs. We recently did our finances for the first 4 months out from Mexico. About a month of this was on passage, where it is difficult to spend money, but to balance this, we purchased a huge amount of groceries and alcohol in Mexico - enough to last us for 6+ months.
Our expenses in Canadian dollars for a little over 4 months are broken down roughly as follows:
Food $1500 (we have used about 50% - so $750)
Booze $350 (we have used about 70% - so $245)
Boat upholstry project: $200
Trade items $100
Total: $1495 with about $850 worth of groceries and booze left on board to date
Agent fees $330
Souvenirs $300 (note we also traded for some items)
Boat Parts $60
Grand total is $3660 - about half of which is for food. We eat well on board, but do not eat out often, in particular in French Polynesia, where prices even for street food can be high. Note that these costs do not include things like travel home or haul outs, which should really be amortized over this period. We were also lucky in being able to carry out repairs of the roller furler bearings and the traveller with assistance from fellow cruisers. Without their help, we would have incurred labour and additional parts charges for these projects. Still, it is nice to be able to say we are cruising out here for less than $1000 a month. Adding in a yearly trip home and haul-out/boat maintenance, this number would be closer to $1500/month.