I had the distinct advantage that I was my own manufacturing cost, and I was young and didn’t value my time that much.
But as a designer, I was able to develop the designs at the pricepoint. For example, take your “+” symbol. Mount it to a 1x2x6 bar of aluminum, it is a bookend. Take your “+” symbol, lay it flat, drill 5 holes, you have a candle holder. A CNC router will cut those “+” symbols all day long at the cost of depreciation, floor space and electricity – cheap. Then have those candle holders on your tables and offer both. All large manufacturers stage with a range of products, look at C&B, Ikea, etc for inspiration.