Pricing Quick breads

It really depends on so many factors. Not just what we think, but what the going rate is in your area (city, state, country), your costs, travel costs, how much you want to make after costs (profit), and probably a few other things I'm missing. For example: a cookie that goes for $5 in one place may go for $7 or even $2 in another place. But I'm right there with you, pricing is HARD.

You might want to price similar size items for similar prices (if they cost about the same to make). Loaf cakes and quick breads are the same where I am, so I would price them the same (and label them the same). Smaller products also take more time and labor to make, so price them accordingly. You may be able to knock out 32 minis or 16 loaf cakes from one batter, but that doesn't mean you charge half. You are packaging 32 items instead of 16, so more glazing, more bag ties, more labels, more cleaning, more them spent per batch. You want to make it advantages to purchase the bigger ones, so the smaller ones should be a little more than half the bigger size, in my non-expert opinion.

For your first market, do only a few bundts, but have an order form ready to take orders. No one wants to walk around with a full size cake. Chances are your bundts will end up only as a display pieces. Or not, it really depends on your area and your market-goers' spending/eating habits.