Cost of photovoltaics with storage

Prices are currently rising somewhat, material is becoming significantly more expensive and harder to obtain. Nevertheless, the offer seems quite high to me.

Possibly a defensive offer. The books seem to be more than full everywhere

A different question: Is it actually common when commissioning the local installation company to pay for the materials in advance? In my case, that amounts to 65% of the total sum and unfortunately does not excite me…

Whether this is common, I cannot say. However, in 2020 it was an offer for us, we placed an order and payment was after performance fulfillment in September 2020. We had agreed at that time, because it was not clear how the feed-in tariff would look in the future, that we would have a special right of withdrawal if it fell away by the time of implementation. This was contractually agreed. In return, we waived a 3% discount.
My gut feeling tells me, why should you pay in advance for the material? Nobody wants to do that for cables and sockets, etc., for electrical or ceramics for the bathroom either.
Sounds questionable to me.

Only companies with liquidity problems do something like that, which is a very bad sign in these times.

The legislator stipulates in § 641 of the Building Code that payment is to be made retrospectively after completion of the work or in partial acceptances.
Why one would want to deviate from this ...

If a craftsman wants this, then he may
a) have liquidity problems; only receives materials in cash and no longer on account from the building materials dealer
b) wants to bind you to himself, intends to carry out the order significantly later than he (verbally) promised you

I would refrain from this, if there were a choice.