Jackpot Party have a monthly 100% match offer to a maximum of £100, which they offer to all their members. (Bigger players get more frequent offers and more generous offers, but the 100% to £100 is a baseline match that everyone gets offered.)
This means you deposit £100, you get a £100 bonus match for a £200 bankroll, and it's on a 10xB wagering requirement which means that £1000 must be wagered in total before any withdrawal can be made.
A 10xB WR is extraordinarily low by industry standards, and is solidly EV+ (Expected Value) for the player. Most bonuses are 30xB WR, 20xB WR is considered 'generous' and 35xB, 40xB or even higher are not uncommon.
When you're working out whether or not a bonus is good value it's pretty easy to work out what you can expect to wager with your bankroll, by simply dividing the bankroll by the house edge expressed as a decimal.
Jackpot Party's slots all have a T-RTP (Theoretical Return To Player) of 95%, which means a house edge of 5%, so from our £200 bankroll we can deduce the following.
200 (bankroll) / 0.05 (house edge) = 4000, so on 'average luck' we'll wager £4000 before we bust out, but of course we don't want to bust out, what we really want to know is how much we'll have wagered when the bonus is expended, and what should be left to withdraw. So if we just halve the above figure, £100 (the bonus) should see us wager £2000 on average luck, which means we'll meet wagering whilst still playing with the 'free' bonus funds.
The wagering requirement is only £1000 however, and £50 of our bankroll should be enough to do that (50 / 0.05 = 1000), so in the simplest of terms, from our starting point of £200, we should finish wagering with £150 left, which is £50 more than we deposited. Basically, our expected result is to achieve the full wagering before the bonus is exhausted, leaving a profit.
Now obviously it isn't quite as straightforward as that, due to the natural variance of slots some sessions will deliver an RTP of far more than 95%, and some far less than 95%, but nothing can change the absolute fact that the offer is EV+, and given that random slots have no memory and do not plan ahead, as every spin of the reels in an independent random event, we can simply look as each month's session as being part of one far longer session.
The more spins we make, the more the overall results will gravitate towards that 95% RTP (in the same way that the distribution of heads and tails on a coin flip always normalises towards 50/50), and the more sure we can be that the fundamentally EV+ nature of the bonus will take effect.
There are some more complications. For example, we want to play as many spins as possible to get as close to T-RTP as possible, so small stakes are in order (spins of 50p or less, rather than £1 or £2 or £5 or whatever), in addition to this, some slots are far more volatile than others, despite having the same T-RTP, so we want to be steering clear of very high variance slots as these generally deliver far more peaks and troughs and take far longer to reach T-RTP.
good old jackpotparty with they're low wagering yippeeeee
