I think you want to purchase an HPLC system. They generally cost ~$25,000 USD. In fact, that's just the fly-by-night sources of refurbished instruments found on Ebay. Actual instrument companies will likely not sell one to someone who calls it a "set". They expect to make money from the service plan for IQ/OQ/PQ and validation, and service plans. So they only deal with incorporated laboratories.
You will need an entire functioning analytical chemistry laboratory to properly prepare eluents, standards and samples. And you will need a contract in place for the disposal of hazardous liquid waste.
I also don't think you want an HPLC. You say oil with terpene, so I assume you don't mean petroleum, but instead volatile fragrance oils and the like. You would probably want a GC. Tell me, in your research into analytical methods, did you find HPLC methods or GC methods. Also what detection does the method call for? I don't suspect terpenes have a significant chromaphore in the US/VIS.