The Jojo card has an expiry date, AFAIK you can get a replacement card for free (only at some main vendors such as Malmo central station). The card costs SEK 20 to buy, minimum load is SEK 50 +20 card fee (non-refundable).

As long as you don't spend much time in Hyllie (assuming that you are coming from CPH), then you could just run into Emporia quickly and then move on to Malmo City Center by bus/train (same ticket). There is an Ikea not far away from Hyllie that you can get cheap food if you are travelling on a tight budget.

GUWonder has quoted the train to Malmo from CPH (it's the same price to CPH City), and the bus costs 22 SEK without Jojo card, so it will be 17.6 SEK with the card.

You need to load a minimum of 100 SEK (or increments of 100).