Do it all on a PA38, its probably the best 2 seat basic trainer commonly available and I have taught on them all. A nice option if you can afford it is to do all the PPL on a PA38 then do an IMC on a PA28 as they tend to be IFR equipped and you are combining a rating course with a type conversion course and then you can utilise the 4 seats for taking friends flying for petrol money.
Good luck,
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