Having a few hours in Weedhoppers, I'd venture that it has enough handling ideosynchrasies that learning to fly on one would be exciting enough that the lack of ailerons wouldn't significantly make life easier!
Anyhow, let's try and look at this impartially (I hope that I can do this, since I fly 3-axis microlights, flexwings and "group A" all fairly regularly).
Costs of learning vary around the country, and depending upon what you want to fly. Similarly, the costs of buying an aeroplane or share vary. So, let's try and be impartial here, I'm going to set myself a few basic rules:
(1) Compare in about the same place
(2) (Almost) nobody learns in minimum hours - let's assume 20% over the minimum - so that's 54hrs for a JAR-PPL(SEP), 38.4hrs for an NPPL(SEP) or 30 hrs for an NPPL(M).
(3) Stick to reasonably basic modernish 2-seaters, you can always spend a lot more, whether in microlight or group A.
(4) Cost of charts, landing fees, etc. is likely to be similar(ish) so we'll ignore them.
(5) PPL (whichever flavour) completed within 1 year's club membership.
(6) No taildraggers (I like taildraggers, but I'm sticking with "easy" for the new pilot). Note that both 3-axis microlights and group A offer cheaper aeroplanes with the tailwheel at the correct end!
(7) Show purchased aeroplanes with similar running costs.
I'm going to pick Sywell for an example, because there are good microlight and group A schools there, it's roughly central in England, I happen to like the place, and both schools prices are shown on their websites. So, let's start with learning to fly
Learning on a flexwing
Fixed fee at Flylight, 25 hrs, groundschool, etc. etc. : £2,485
Extra 5 hours: £455
Total = £2,940 (This was in a Pegasus Quantum)
Learning on 3-axis
Fixed fee at Flylight, 25 hrs, groundschool, etc. etc. : £2,665
Extra 5 hours: £490
Total = £3,155 (This was in Cosmik Eurostar)
Learning on a light aeroplane - to NPPL(SEP)
Initial 15 hour package including club membership = £1,875
Extra 23.4hrs = £2,925
Skills test = £95
7 Exams = £175
Total = £4,970 (This was in an Aero AT3)
Learning on a light aeroplane - to JAR-PPL(SEP)
Initial 15 hour package including club membership = £1,875
Extra 39hrs = £4,875
Skills test = £95
7 Exams = £175
Total = £7,020 (This was in an Aero AT3)
Now, let's look at buying ourselves a cheap but sensible 2-seat aeroplane. I'll use as my source
www.afors.co.uk (I'm exercising some judgment here) and pick the cheapest sensible looking first aeroplane that I can find.
For a flexwing, I'll pick
this Pegasus XL-Q, at £2,750
For a 3-axis microlight, I'll pick
this Cyclone AX3, at £4,500
For a "group A" aeroplane (inevitably PFA if we're going for cost),
this Rans S6 at £17,750.
So, comparing the costs of realistically getting a PPL, and then buying outright your first, cheap-to-run, 2-seat aeroplane, I get the following:
NPPL(M), flexwings: £2,940 + £2,750 = £5,690 (cheapest)
NPPL(M), 3-axis: £3,155 + £4,500 = £7,655 (+£1,965 / 34%)
NPPL(SEP): £4,970 + £17,750 = £22,720 (+£17,030 / 299%)
JAR-PPL(SEP): £7,020 + £17,750 = £24,770 (+£19,080 / 335%)
Or of just learning to fly, ignoring purchase costs
NPPL(M), flexwings: £2,940 (cheapest)
NPPL(M), 3-axis: £3,155 (+£215 / 7%)
NPPL(SEP): £4,970 (+£2,030 / 69%)
JAR-PPL(SEP): £7,020 (+£4,080 / 138%)
G
(A few disclaimers...
i. This is only one airfield, and one set of adverts
ii. I know several of the people selling flying/aeroplanes above. This is co-incidental and I hope hasn't affected my arguments.
iii. Buy a share, it's much cheaper than buying outright, whatever you're flying
iv. Don't forget to work out the cost of flying the aeroplane afterwards! There are loads of threads about this on PPrune, so I'm not going to start another one.) If you want a really rough rule of thumb, take the cost of fuel, add 150% and you'll be about right for most powered flying machines.
v. If you're really cash-strapped, don't forget gliders.
vi. Whatever you fly, you'll still need charts, landing fees, etc.
vii. Never forget that you can usually trade hours and experience on any one aircraft towards qualifications to fly another.