As someone who loves to DIY I understand the allure of making your own tank- not sure you will save any money at all- once you buy the glass and silicon masking tape and squares or glass cutters( which you might already have granted) you are already probably $150 in. You can get something close in dimensions with a warranty and proven track record for similar costs, maybe a tad more. Used tank is also a good option. That said, often the draw of DIY is not savings, but the pride of having built it yourself- which I totally get. Personally as others have said the risks to livestock and floors are orders of magnitude higher than the money you might save. But, your comfort with that risk and faith in your skill to build a DIY tank only you can know. As mentioned low boy 4x2 tanks are about $110 in my area. A little nicer deep blue tanks are about $300. Aqueon/Marineland fall in between...