So im pretty much working with a 0€ budget and can't spend money on asesprite rn. I made this plugin for gimp to help with creating assets and I thought somebody might find it useful too.
The plugin allows you to export the currently selected layer to a png file. It uses the layer's name as the filename and allows you to automatically trim the whitespace around your object (just like asesprite). You can also bind a key to this script, making life even easier. Installing and using it is detailed in the readme file.
I know gimp ain't the best way to go about creating assets. But with no budget in mind I found this be the best way (at least for me).