[Answered ]-How do i access a dictionary value in a django template?

You can not subscript in Django templates. What you can do is just add an attribute:

def index(request):
    queryset = Listing.objects.all()
    for listing in queryset:
        listing.highest_bid = listing.product_bids.latest('bid')

    return render(
        request,
        'auctions/index.html',
        {
            'listings': queryset,
        },
    )

and thus render with:

{{ listing.highest_bid }}