How can i get more storage on my Samsung galaxy J1 mini.

A

AC Question

Hi guys, being of an advanced age, i am only on my 2nd phone.
Recently my galaxy J1 mini 8gb has been alerting me that i have no storage space. I have a 16 class 10 sd card installed.
Over time i have deleted every app except one slot game. I have cleared all caches and sent everything i have left that can be sent to my sd card, the thing i use my phone most for is writing emails to friends o/s, I've tried to put my emails onto my sd card but it won't let me. I've done everything to clear this storage problem but i don't want to delete my old emails because there are too many memories in them, if i send all of my old emails to archives in my gmail folder and unburden my phone email storage, will this help, also how do i even upgrade my phone to have more internal memory or do i have to buy a new one?
I understand the fellow in another question on this site who is irritated & says if people didn't buy cheap phones the companies wouldn't make them but my partner is on a bridging visa, so has no income & is terminally ill & i am on a lone carers pension so not everyone has a choice to buy a decent $1200 phone much as i would love one we're stuck with this, which for the most part works efficiently. anyhow apologies for that i felt an explanation as to why some people buy cheaper - Any info is much appreciated, cheers.