'Cheap' might come with baggage, but it is still a perfectly good, simple, adjective of comparison.
What is the opposite of expensive? Well, you could use one of a dozen euphemisms, but to many people unswayed by the vagaries of fashion in words as in all things, 'cheap' is still a sound word, and spades are still spades.
Many of your customers and potential customers want cheap housing, cheap travel, cheap food, and so on. And when they look for a cheap electric bike, they're not looking for a sub-standard machine, but one like yours - sturdy, well-built with tried and tested components, and priced sensibly. (Do you want me to write your advertising copy?)
Allen