Upload & Sell: Off
Some factors to consider when archiving digital data: location, medium, equipment, encoding, sourcing, migration.
Location: Copies of data are safer when located in more than one location. This protects against theft, breakage, fires, natural disasters, etc.
Medium: Choices of medium affect lifetime of data stored. OP's use of burnable CD/DVD limits reliable retrieval to a few years (dye-layer decay, oxidation of reflective layer). Hard drives have lubricated mechanisms and capacitors with finite lifetime. Tapes can be archival in time, although Earth's magnetic field takes a toll.
Equipment: Even with (static) medium intact, loss of equipment will render the data inaccessible. Talk to NASA about this! Besides the peripherals themselves, the rapid progression of technology can make the cables, host controllers, and buses obsolete. In the limit, the entire original machine may be needed to retrieve data.
Encoding: However thinly, data is always archived in a structured way. To retrieve that data, your future system must understand the archiving format or filesystem. This is beyond the encoding of the individual files which may themselves vary (Canon RAW, ZIP, JPEG, Excel, etc). In the latest twist, high-end drives can encrypt their content with onboard hardware. Will you or your successors remember the password?
Sourcing: If you purchase several storage devices of the same model, these may contain flaws in design or manufacture that cause failure in a narrow span of time, or failure from a common event (e.g. power surge). The failure of those devices is correlated, meaning you don't have the backup redundancy that the numbers suggest. With mass storage ever more concentrated to fewer OEMs and technologies, maintaining archives across two independent storage sources is becoming harder (and more expensive).
Migration: The best route to data longevity is copying the entire archive from past to present forms of storage. The penalty is labor, cost, and the real danger that the transfer fails and the failure is not detected. To minimize the impact of human error, migration should be performed as infrequently as possible, which means the decision in other factors should favor longevity.
I've been messing heavily in storage for over three decades: punched cards, pack drives, Winchester, 9-track, audio cassettes (TRS-80), all the floppy form factors, CD-RW, QIC, 8mm, VXA, DAT, SDLT. For many of these, I either wrote devices drivers or backup software. Currently, my main personal machine has SAS HDD, SATA HDD, SATA SSD, SATA DVD-RW, SCSI Exabyte 8mm.
In answer to nolaguy, the archival value of SSD as a medium is largely unknown. To my knowledge, the only product to address this market explicitly is the Sandisk Memory Vault with a projected lifetime of one century. While I work for the company, no promises on that claim!