sa hardware biz, if you go small, big guy eat you alive. only advantage small guy has over big guy is that small guy is hungry and has a riskier appetite, willing to take on riskier customers. walay contractor mu palit ug cash, rare kayo.
BIR is a required but as a hardware store, you have to manage your VAT input against your VAT output MONTHLY. Penalties can be very high. that's where managing your cash flow comes in handy. a hardware store, no matter how you put it is a TRADER. he does not produce anything but rather "buys and sells".
Another point on how a big store can kill a small store is how big stores buy in volume and get bigger discounts from suppliers. For example on cement. To buy direct from a cement factory is impossible unless you secure a quota. To secure a quota, you need to place a cash credit facility. Normally involves millions. Margin on cement is piso piso ra. Patay paka sa delivery. Where the magic is to the quota holder is achieving sales targets set by factory. That nets in quarterly rebates and annual rebates. That is pure profit (after a 30% income tax) Same thing with paint and PVC products. (more so paint than other items)
500k sales a month in hardware is not equal to a profit margin of 10-20%, you would be happy to average 10, but I would expect around 5-8%. If you mark up too much, people end up buying from the bigger players. its really not hard to sell a lot, but its hard to convert your sales into a profit if you don't get paid on time or even get paid at all... the risk is all there.