Erk, this is a tricky one! Its pretty difficult to save money actually assembling models. After all, you already have the models to assemble. If anything, you probably need to spend MORE money on this bit!
Why? Well, top quality tools for cutting things of sprues are worth it – though you can pick them up cheaper in a hardware store than a hobby store. You still need to make sure they are fresh and sharp though, or you’ll be ruining expensive models.
The same is true with glues. You can probably save a little by getting plastic glue from general hobby stores, and superglue from hardware stores rather than gaming shops, but you need decent quality glues to keep your models together with a good method of application to stop you spraying glue everywhere and ruining models.
Where you can save money, though, is making sure you are taking full advantage of your bits box and kit bashing. Assemble models you can use, and save money to do it.
Need 2 units of Rubric Marines, one with warpflamers and one with bolters? If you have a unit of unassembled chaos marines floating around, you can pick up a few heads from either bits resellers or their parties, and kit bash them up. I have absolutely tons of unassembled chaos marines from previous projects, so its a no brainer for me. Its not worth going out and buying all the bits – that’d cost more than just buying new Rubrics, but if you have them lying around, think about reusing them. Be careful if buying third party bits though – you aren’t going to tournaments or official painting competitions with those. If its for casual gaming though, go for it.
One of the single best money savers when it comes to building units is to know exactly what models and parts you actually have already. Need a Chaos Lord for a game? You can probably knock one one if you have a fair few custom parts across marines and chaos already. Seriously. Spend a few hobby sessions just sorting out your extra bits and boxes of unused models. I’ve lost count of how many times I’ve accidentally doubled up on a cool model it turns out I already had. (I may have 3 Eldrads… and at least 5 Dark Elf Sorceresses.)
Kitbashed models may not look quite as good as some of the brand new models … but then sometimes they can come out looking even better to your eyes, and be genuinely unique. In addition, moving beyond the Cheap gamer for a moment – practising kit bashing for this sort of thing really improves your conversion skills for actively putting something really special together, without costing much right now. Save the money for all the bits for your unique centrepiece … but practise putting bits together now.
In addition, there are lots of techniques to improve the finish of kitbashed models. Drilling out gun barrels is fantastic for top end models, and its better to practise on knocked together bits than a forgeworld special character! Assembling odd bits often needs filling with green stuff, zap a gap glues or liquid green stuff, and this sort of thing can ruin a model. Practicing on these simple cheap options can really raise your skills.