There are a few options depending on your size garden.
Fleabay has many 12v pump, the type used on ag sprayers.
Hand pump sprayer are available in many sizes too.
Also, nurseries use tanks , usually on wheels with air pressure to distribute liquids by wand.

Depending on how long the run and height difference is a submersible pump will work well. You just need to get one that will accommodate head pressure. Most come with info on the change in flow for different heights above the pump placement. I would go with a mag drive as they will handle the start stop in flow better IMO.

If this is for outdoor you best bet is something like a sump pump. Just wire in a switch to the hose end. Easy way is to rewire an aftermarket float valve switch that piggy backs onto the plug (think christmas lights) into a push button attacked to the hose end. They are also usually fitted for garden hose attachments out of the box. You can also just use a ball valve ect but over time might not be good for the pump but you can prob get away with it as cheap as sump pumps are (100 bucks or under usually). You can also wire your own switch if you are comfortable with that. simple push button or switch depending on how much watering you are doing. Some people arent and would rather just hack something.

Even easier is put a hose on and kink it between plants.

Home depot/Hardware store for all of it