Honestly, this saddens me a bit. Don't get me wrong, I fully agree about the cheek of people accepting drinks etc with no intention of reciprocating. But having very little disposable income seems to make me a bit of a social pariah.
DH and I don't have much money at the moment. We are furiously paying off our remaining small amount of debt, and will be debt free in three months, just in time to coincide with a decent gauranteed pay rise for DH and the arrival of our new baby
. So we wont be skint forever, but for the past year or so we've been very frugal.
Changing habbits has been difficult. Going to soft play once a week with my lovely and generous friend, we would usually buy a 'round' each, hot drinks, cake for adults, then more hot drinks and lunch for the kids. At first lovely friend insisted on buying me tea and cake, even when I said I couldn't afford to do the same. I started bringing packed lunch for DD, and so friend would then buy DD a packet of chocolate buttons or similar so she could have the same as her DD.
It got really embarrasing because I'd made a promise I wouldn't waste money on over priced soft play food when I honestly dont think DD would miss it if it wasn't on offer. So I wouldn't return the favour, and in the end had to have a really embarrasing talk with friend about how I was going to just pay for my own stuff and I really couldn't accept any more treats because basically I couldn't spend the money returning the favour. And to be honest doing this took away a little of my pride, having previously been very free with my money and getting into debt as a result
As for the splitting the bill thing, a few years ago (when earning a fair wage) I would have agreed whole heartedly. But now I've been invited to a big meal out with ex collegues next week, and decided last night I just can't go. Not because I can't afford to pay my share, but because I know from experience that the wine will be flowing, the steak and king prawns will be ordered at extra cost, and then the bill will be split equally amongst everyone there. Which means pregnant me ends up paying for other people's alcohol and extras, when in reality I could've just ordered something cheap from the menu and had a fab time catching up.
So I've decided not to go because I really don't want to be talked about as 'the one who gets her calculator out at the end' 
I know you are really talking about the takers in life, rather than the genuine skint. But sometimes people get the two mixed up and it means me missing out sometimes.
Apologies for any typos, trying to multitask and am terrible at it!