It's easy to look back on Escorts as being the cheap cars of their day. The Rally Pack was an aspirational model released around mid-1977, so to see just how affordable it was back then, I took a look at the price and net income of the average male worker in Sep 1977.
The car itself cost $5152 (including sales tax), and adding a couple of reasonable extras, i.e. sports suspension ($30), 70 series tyres ($40) and a tinted, laminated windscreen ($89) brings the total to $5311. These figures were taken from a road test of that exact model in a magazine published in Sep 1977.
From the Australian Bureau of Statistics I learned that the average male weekly wage for the Sep 1977 quarter was $204.60 a week, or $10,639.20 a year. Assuming no deductions, the income tax on that amount for the 1977-78 financial year was $2,301.65, leaving $8,337.55 net. So, a Rally Pack with a few extras cost 63.7% of the net disposable annual income for the average male worker in Australia. Doesn't sound cheap to me.
By way of comparison, you'd need to spend about $37,939 today to use the same percentage of your net income. This is based on the latest Nov 2012 average weekly male wage of $1489.10, and annual tax payable of $17,874.29 (incl. medicare levy). That puts the price and specifications of todays cars into some perspective for me, especially in the small car market the Escort once occupied.