There are some independent car locksmiths who can clone an existing key or program the car diagnostics to accept a new remote. They won't always be cheaper than a dealer, it depends on whether they can obtain an aftermarket fob or have to buy from Hyundai.
I had a key made up for my previous Santa Fe. It involved cutting a new key blade to match the old one and cloning the transponder from the old one. Cost was just over £100 from Bournemouth Car Keys. A new 2 button remote was slightly more as it had to be bought from Hyundai. At least I had a spare key then, even though it had no remote.
Some older cars don't need access to diagnostic programming equipment to add a remote, it's done via a button hidden below the steering column. The car can be set to respond to a pre owned remote fob. Unfortunately I don't think your i10 is one of them.