Its doable
just depends how far you want to go
A PIC is perhaps the easiest way to go but you need to write then program a PIC chip.
another method is simple TTL or cmos
just have two up counters that count to 7
when 7 is obtained it turns off the fans and traps the puck (thats the hard part or perhaps have a trap door that opens then traps the puck.
upon inserting a coin the puck drops to a tray and play begins (kinda like a billard table)
look up using google or ? for up counters with a single digit
take the outputs and using gates (IC chips like 7400 or 4011) you analyze when 7 is reached.
another method would be a simple counter like the 4017 and a few gates to analyze the outputs into 7 segment digits.
If wanting to use a PIC then
PCB Heaven has a one digit counter but the circuit and code would need to be written (lots of work if never used a programming language.
micro switches at each goal to instantiate the counters.
metal pucks are an easy way to count the goals or infrared red sensors.
micro switches would work but IMO would wear out very quick and not as reliable??
if you could get a PIC programmed then you could cut your costs down.
my eatimate = 1-4518 counter(2 counters in one package,
2-4511 BCD gate,decoder/driver,
1-4013 gate
couple of transistors, couple of relays, switches and you have it.
now go do a search
look up decimal counting unit