Shops are Ages Away from Accommodation, What do?

Hey, hi,
I'm a newbie to TSR, but I have a REALLY important question.

I'm going to ManMet in September and my accommodation is on Grafton Street. Its not too far away from ManMet. But it IS pretty far away from the city centre.

I want to shop at places that are cheap like Aldi, but is it really plausible to trek like an hour and a half to get shopping?

My boyfriend advises against it because frozen things would melt on my way home. Would ordering online from somewhere like Tesco be any better?

Are there any busses I could get to shorten my journey?

Or do any of you live in the area I'll be living in and know of some shops closer?

Thanks in advance for the help.