Small third-party manufacturers often have residue at the end of a job, and, in order to keep from being overrun with that residue, they dispose of it via eBay. You can buy what's left of a 5000 piece roll of SMD passives for, typically, $5US, and sometimes considerably less. Freight cost might be more than the cost of the components. I routinely replenish my stock of 0805 and 0603 (that's the smallest I can easily manipulate) resistors and capacitors in commonly used values, e.g 1-kOhms, 10-kOhms, etc, 1 nF, 100 nF, etc. in that way as the opportunity arises. You do have to "read the fine print" and look at the picture of the roll or packaging, though, to ensure you're getting something you can use.

In your case, you might consider buying say, 4000, and then reselling 3500. You might be able to make the transaction "revenue-neutral," in that you sell the 3500 for what you paid for the 4000. People who use parts in dozens don't really care whether they get 2000 or 3000 too many.

RE