I find it easier to cost things up on a monthly basis,
add up every outlay in a month, as scotserve says, include stationary, the lot.
Then work out how many bathbombs etc that you can sell in that month and work out the individual retail price of each product, enough to cover costs and give you the profit you want, ie a 50% profit margin for arguments sakes.
for example, say your monthly costs total £500 and you estimate selling 300 bathbombs you would need to sell each bathbomb for £1.67 to cover your £500 costs, if you wanted to add a 50 % mark up on each product you'd need to sell each bathbomb for £2.50
obviously £2.50 per bathbomb is probably too much lol but the principle is the same, work out costs per month, figure out how many bathbombs you're likely to sell and work the price out that way
