It's quite a hassle to run an unmodified ZX Spectrum computer in North America.
The easiest of the challenges is finding a suitable cassette tape player. There are several choices here, including walkmans, boomboxes, etc. I was able to find a personal tape recorder at a thrift shop and paid $5 for it.
Power was another issue to resolve. Two items were needed here: a $9 step-up transformer which outputs 220v and a $7 universal power adapter to allow the ZX Spectrum British-type plug to be used in a North American outlet.
Getting a picture was the hardest. Without modifying the machine, a TV that can receive UHF channel 35 (36 according to the computer's manual) and which has a PAL analog tuner. I bought a portable LED TV online for about $50.
Storage - $5 thrift shop personal recorder
Mono tape players work best. Thrift shops often have very interesting older electronics and I visit them regularly.
Power - $9 transformer and $7 power adapter
You can get these transformers at electronic hobby shops. There are far more expensive transformers to be found on online shopping sites, but these $9 ones do the job.
The power adapters are commonly found at Walmart, convenience stores, electronics chains, or electronic hobby shops.
Picture - $50 portable LED TV (PAL analog tuner)
Getting a suitable TV was the hardest part. Full-size LCD TVs often don't list whether they support PAL input or not. I bought this tiny portable TV from eBay because it has an analog tuner and because its specifications listed an acceptable UHF range.
I have not modified the Spectrum in any way to use it with this TV.