Absolutely, the material cost for such a system is about 7-10k strongly dependent on the battery. The other ~10k is for setting stuff up (which takes about 1-2days).
The small balcony systems can be setup by pretty much everyone. They also have the best ROI compared to bigger energy producers.
A reasonable sized solar power system with around 10kWp and 10kWh battery costs at least 16k€ in Germany when done by a professional. Depending on your power consumption in general this can be a bad investment even with a heat pump. Therefore I would separate this from the costs of a hwat pump, since it is not strictly required. Especially since you can get energy plans selling power for ~26ct/kWh.
This was the tipping way in Germany too, at least when you mostly paid with cash. IMO it was mostly used to speed up the payment process, even when recieving okayish service. Much faster to return 8€ than 8.47€. With digital transactions this is not necessary anymore. Ignoring the 1/10 exceptional service you get rarely.