Tender software at an affordable price

The digital tendering process is a good way to obtain comparable offers. It is important that the output format can be easily read by the contacted companies. I would choose GAEB as the output format. The price of the software is determined by the input options and the ease of input. It is practical if the software already has service texts or can import them. Of course, these service texts also cost money. After all, people should be able to earn a living from good work. You asked for a cheap solution - look for software with GAEB output. Based on my quite extensive experience with software for the construction trade, I think that cheap software causes more work than a mature and naturally more expensive one, because with simple programs you will repeatedly reach the limits of representing your project. From €3000 you get something reasonable. That is also the reason why, although I get such software cheaper and did the awarding to the craft myself, I refrained from such software.

With us, it works quite brazenly - we have an offer made (preferably also with a personal meeting and discussion of how we want things), cross out all prices, and then forward this as a request along with the respective information (construction folder etc.)

I find that a bad - and little constructive - style. The craftsman who gets the contract has it in mind that you do not appreciate the work of colleagues - in case of problems, which always arise in house construction, the atmosphere of conversation will therefore very likely be characterized not by openness, but by mistrust. I advise against this method.

It is practical if the software already has performance texts or can import them.

A layperson might initially (rightly) think that creating such texts oneself requires quite some experience (and hopes for such software are often also of the kind that it might generate nicely professional-looking texts if one only enters general material types and dimensions). But even more experience is needed to highlight traces of sponsorship in such texts: there are performance features that are either actually unique selling points of a manufacturer or at least are named that way only there. As a result, the text never openly states "Manufacturer A", of course, but the "supercalifragilistic sensor control" exists only there, and installers who only install technology from Manufacturer B or at least have significantly better purchasing conditions there (e.g., not so uncommon with heating boilers) are practically kicked out.

Which programs are recommended for a simple single-family house?

Excel.

As 11ant has nicely described, the difficulty is not the graphical frontend where the tender texts for the individual items are compiled to then output a GAEB. You won't get a neutral tender without product specifications perfectly using ausschreiben.de and the like, because manufacturers only put positions here that directly target their own product or even demand this.

You can tender individual construction projects with Excel + GAEB interface (<€100 for commercial use). I have already tendered million-euro projects at work this way. ORCA AVA would certainly be more comfortable here, but Excel gets the job done, especially for a one-time individual construction project. The individual items have to fit, but your AVA won't conjure them up for you either.

But even more experience is needed to highlight traces of sponsorship in such texts

That’s true – for this, e.g., the standard performance book for construction (StLB data) or the Sirados collection help. Of course, these cost money. Export to GAEB via Excel is possible but not really suitable for laypeople. An alternative to tendering is to involve the professional and solution expertise of the craft company. That’s how we solved it. Our architect did an amazing job, which also comes from the fact that he did not act as all-knowing but showed respect for the skills of the trades and their specialists. We consulted them during planning and in this way received a number of excellent solutions that suit us perfectly and are not within standard thinking. You are not buying a price or discount, but a housing for your life.

I find that a bad - and not very effective - style. The craftsman who gets the contract has in mind that you don’t appreciate the work of colleagues

Sorry but - what nonsense. 1. Does that mean you always take the very first offer? Lest someone think you don’t appreciate their work? We have nearly identical offers with price differences of 25%. 2. The same applies to kitchens. Here we were even asked, "If you get a better offer elsewhere, we would be happy if you give us the opportunity to make a counteroffer." 3. These are not little children who cry if we then cancel anyway. 4. I still have the option, in an emergency, to decide on the more expensive one who made the better personal impression on me.

"Sorry" accepted

1.: No, I do not take the first offer that comes along. This inference is not logical.
2.: Kitchen sales are extremely discount-oriented to induce purchase decisions. The "phrase" that one should try to find a cheaper offer is very transparent to me as a sales trainer. Applying this principle of enormous discount pricing to the craftsman world is misguided.
3.: These are business people. In the currently excellent economic climate, the best companies will not even respond to you. They have no interest in such games.
4.: Of course you have a choice. But only from the circle of those who respond to this method. The best are not among them.

Creating an offer takes hours of effort, which is only paid upon closing. This is acceptable and usual. Offers are also generally subject to confidentiality. This, of course, does not only apply to prices. Breaking this without being asked is bad style. The temptation is great because the benefit appears large. The temptation is great because others do it too. It remains bad style.
The best companies currently pick their customers. Why should a good craftsman deal with someone who already documents in the inquiry that they are not ready for a trusting cooperation?