Bhagavad Gita is a spiritual treatise and has universal appeal is available for mere $.10 from Gita press, Gorakhpur, India. This copy of Bhagavad Gita contains all the 700 shlokas verses in Sanskrit in original form.
Even an authentic commentary of Bhagavad Gita containing all 700 shlokas verses along with English and Hindi transliteration is available for mere $1 from Gita press, Gorakhpur, India.
Despite Bhagavad Gita being available at a very highly subsidized cost, even below the production cost has no takers worldwide. Reason being nothing in Bhagavad Gita can be understood literally, one has to follow path of contemplation (chintan) to reach the hidden underlying meanings.
More than where original written Srimad Bhagavad Gita is kept is the indulgence in teachings of Bhagavad Gita. All the publications of Gita press are truly commendable. Their authors are very authentic and commentaries are to the point. Not only this but commentaries on Bhagavad Gita and 11 principal Upanishads by Adi Shankaracharya (an enlightened one) are also available.
To understand Bhagavad Gita we only need mastering the delicate art of contemplation (chintan). Initially it seems difficult, maybe very difficult yet not impossible.
The spirituality detailed in Bhagavad Gita is very unique and not the literary kind. As per Bhagavad Gita human beings need taking an inner journey towards the spirit existing in their heart as soul atman. Only then one can truly realize that they were a spiritual traveler and not the manifest physical human form