As Andy says, it's hard to guess costs in Thailand, but if a PPL is 5000 USD then it sounds like flying it a fair bit cheaper than over here in the UK (where a PPL will cost around $7500-$10000 depending on where you do it). However, I think it is fair to say that if you plan on flying regularly after the PPL (say 30+ hours per year) then after a couple of years the initial cost of the PPL becomes fairly insignificant - if it is hard to afford a PPL, then it's going to be hard to afford to fly regularly afterwards.
Over here the cheapest way to fly regularly once you have a PPL is usually as part of a group - club hire is best if you're flying less than about 20 hours a year and aeroplane ownership is usually the most expensive option. Groups also have the advantage of letting you take the aeroplane away for several days, over here clubs charge so much to do this that few people ever do.
It's hard to guess what the costs of a group would be in Thailand. You first buy a share in the aeroplane - the cost of this varies depending on the size of the group, but as you're touring regularly a small group is best (the smaller the group, the better the availability) so a fifth share in a typical tourer (PA28/C172) would probably start at about $10k or so. You then pay a monthly charge for hangarage/insurance (say $100 - $200) and an hourly cost which is really fuel plus maintainance (<$100). These are very rough figures and probably an overestimate (based on converting the UK cost to USD), but it should give you a general idea.
Good luck
Also, I wear glasses for driving and have had hypertension (high blood pressure) for a number of years which is well managed via a daily dose of Tenoretic.... Could they prevent me from getting a PPL?
I'm not a medic and don't know the Thai rules, but I'd guess that unless things are bad then there shouldn't be a problem. I need to wear glasses all the time but my uncorrected eyesight is still good enough for a commercial medical, so I guess it needs to be quite bad to prevent you getting a PPL. As for blood pressure, my father in law is on all sorts of pills for that and has a FAA medical, so that can be done too. Obviously you need to see an aviation doctor for an official yes or no.