I generally agree about the early game gold crunch, but as dexters pointed out, Samurai come far enough into the game that you should have a good strong trade economy and a handful of strong cities with roads and luxes sold. I find by the late Classical Age, I've got enough gold to comfortably build and maintain an army. Samurai can be rushed early in Medieval, but still you should have a strong economy by then.
If you're having difficulties, suggest making sure you've got your trade routes maxed and running to the best cities you can. I find that making one city my trade city and building the caravansary and market (and EIC, Colossus, etc if available) is the way to go. You don't need those buildings in every city which will save you a few precious hammers. I try and always trade international because the returns are better, but if you don't have access, you can always safely go to a CS.
Make sure you're selling your excess luxes. I find I can get 6GPT from them reliably, without a DOF. I avoid DOFs until research agreements become available as well, because they offer essentially no benefit, but you have to pay with spare luxes or gold when they come begging.